KR20190057371A - Beam scanning device, pattern drawing device and method for checking accuracy of pattern drawing device - Google Patents

Abstract

The exposure apparatus EX projects a working beam LBn onto each of a plurality of reflecting surfaces RP of a polygon mirror PM rotating around a rotating axis AXp and applies a beam LBn to each of the plurality of reflecting surfaces RP And the reflected beam LBn for processing is scanned on the substrate P via the f? Lens system FT. The exposure apparatus EX includes an origin sensor for generating an origin signal SZn each time a plurality of reflective surfaces RP of the polygon mirror PM are set to predetermined prescribed angles, And a correction unit that generates a correction origin signal SZn 'that is corrected by a correction value corresponding to the deviation amount of the time interval of the origin signal SZn generated corresponding to each of them.

Description

Beam scanning device, pattern drawing device and method for checking accuracy of pattern drawing device

The present invention relates to a beam scanning device for scanning spot light of a beam to be irradiated onto a surface to be irradiated of an object, a pattern writing device for drawing and exposing a predetermined pattern using such a beam scanning device, ≪ / RTI >

2. Description of the Related Art Conventionally, a technique has been proposed in which a spot beam of a laser beam is projected onto a workpiece (an object to be processed), and spot light is scanned in a one-dimensional direction by a scanning mirror (polygon mirror) In order to form a desired pattern or image (letter, figure or the like) on the article to be formed by moving in the sub scanning direction, for example, a laser process such as the one disclosed in Japanese Patent Application Laid-Open No. 2005-262260 It is known to use an apparatus (optical scanning apparatus).

Japanese Patent Application Laid-Open No. 2005-262260 discloses a galvanometer mirror that reflects a laser beam from an oscillator 1 and corrects the irradiation position on a workpiece of the laser beam irradiated to the workpiece in the Y direction (sub-scanning direction) A polygon mirror for reflecting the laser beam reflected by the galvanometer mirror and scanning the workpiece in the X direction (main scanning direction), an f? Lens for condensing the laser beam reflected by the galvanometer mirror onto the workpiece, the angle of reflection of the galvanometer mirror is controlled so as to correct the irradiation position error in the Y direction on the workpiece in response to the distortion aberration caused when the laser beam passes through the f lens, A control section for controlling the pulse oscillation interval of the laser beam by the oscillator is provided so as to correct the irradiation position error. 8 of Japanese Laid-Open Patent Application No. 2005-262260 discloses a laser light source that emits detection laser light for detecting the end of each reflection surface of a polygon mirror during rotation of the polygon mirror, A detector for receiving the reflected light of light and generating an end detection signal is provided and the timing of the pulse oscillation in the oscillator is controlled based on the end detection signal as shown in Fig. 9 of Japanese Patent Application Laid-Open No. 2005-262260 Is disclosed. In the laser machining apparatus (beam scanning apparatus) using a polygon mirror such as that disclosed in Japanese Patent Application Laid-Open No. 2005-262260, the higher the rotation of the polygon mirror is, the shorter the machining process time of the workpiece, . However, as the rotation speed of the polygon mirror is increased, the deviation of the processing position with respect to the main-scan direction becomes conspicuous.

According to a first aspect of the present invention, there is provided a projection optical system for projecting a working beam onto each of a plurality of reflecting surfaces of a rotating polygonal mirror rotating around a rotating shaft, and for reflecting the working beam reflected by each of the plurality of reflecting surfaces, An origin detecting section for generating an origin signal each time each of the plurality of reflecting surfaces of the rotary polygonal mirror reaches a predetermined prescribed angle; and an origin detecting section for detecting an origin signal corresponding to each of the plurality of reflecting surfaces, And a correction unit for generating a correction origin signal corrected by a correction value according to the deviation amount of the time interval of the correction origin signal.

A second aspect of the present invention is a projection exposure apparatus for projecting a drawing beam onto each of a plurality of reflective surfaces of a rotary polygonal mirror rotated around a rotation axis and irradiating the imaging beam reflected by each of the plurality of reflective surfaces, An origin detecting section for generating an origin signal every time each of the plurality of reflection surfaces of the rotary polygonal mirror reaches a predetermined specified angle; A drawing control unit for setting a time point after a predetermined delay time from the generation of the origin signal as a start point of patterning by the imaging beam; And a correction unit that corrects the delay time set by the rendering control unit for each of the plurality of reflection planes.

According to a third aspect of the present invention, there is provided a projection exposure apparatus for projecting a drawing beam onto each of a plurality of reflective surfaces of a rotary polygonal mirror rotating around a rotation axis, and for projecting the imaging beam reflected by each of the plurality of reflective surfaces A pattern writing apparatus for drawing a pattern on a substrate by scanning on a substrate supported by a support member, the pattern writing apparatus comprising: an origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror becomes a predetermined prescribed angle; A drawing control section for setting a time point after a predetermined delay time from the generation of the origin signal as a start point of pattern drawing by the imaging beam; A correction unit that corrects the delay time set by the drawing control unit for each of the plurality of reflection planes by a correction value according to By measuring the time between the generation timing of the reflected light generated from the reference pattern and the generation timing of the origin signal when the reference pattern formed on the substrate or the substrate is scanned by the imaging beam, And a measurement unit for obtaining a value.

In a fourth aspect of the present invention, there is provided a projection exposure apparatus for projecting a drawing beam onto each of a plurality of reflecting surfaces of a rotating polygonal mirror rotating around a rotation axis, for reflecting the imaging beam reflected from each of the plurality of reflecting surfaces, A pattern writing apparatus for drawing a pattern on a substrate by scanning on a substrate supported by a support member, the pattern writing apparatus comprising: an origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror becomes a predetermined prescribed angle; A drawing control section for setting a time point after a predetermined delay time from the generation of the origin signal as a start point of pattern drawing by the imaging beam; A correction unit that corrects the delay time set by the drawing control unit for each of the plurality of reflection planes by a correction value according to Measuring a time between a generation time point of a photoelectric signal obtained when the photoelectric conversion element is scanned by the imaging beam and a generation time point of the origin signal, the photoelectric conversion element provided on a part of the support surface of the member And obtaining a correction value according to the deviation.

According to a fifth aspect of the present invention, there is provided a projection exposure apparatus for projecting a drawing beam onto each of a plurality of reflection surfaces of a rotary polygonal mirror rotating around a rotation axis, and for projecting the imaging beam reflected by each of the plurality of reflection surfaces A method for inspecting the accuracy of a pattern writing apparatus that focuses a spot light on a substrate supported by a support member and scans in a main scanning direction, the method comprising the steps of: detecting, from each of the plurality of reflection surfaces of the rotary polygonal mirror, Scanning direction of the spot light by the specific reflecting surface in response to a specific origin signal generated when a specific reflecting surface of the rotary polygonal mirror reaches the specified angle among the generated origin signal, Of the origin of the specific origin signal repeatedly generated by the rotation of the rotary polygon mirror Scanning the inspection pattern while moving the substrate in a sub scanning direction intersecting the main scanning direction by a distance smaller than the size of the spot light for a predetermined period of time; A step of repeating the setting step and the drawing step and measuring the accuracy of the origin signal by measuring the shape of the inspection pattern drawn on the substrate or the deviation of the arrangement in the main scanning direction do.

1 is a perspective view showing a schematic structure of an exposure apparatus for performing exposure processing on a substrate of the first embodiment.
Fig. 2 is a specific configuration diagram of the imaging unit shown in Fig.
Fig. 3 is a diagram showing an arrangement of a polygon mirror, an f? Lens system and a beam receiving system constituting the origin sensor in the imaging unit shown in Fig. 2 in the XY plane.
Fig. 4 is a view showing the arrangement of the beam transmitting system and the beam receiving system shown in Figs. 2 and 3 in a simplified manner.
Fig. 5 is a diagram showing a detailed structure of the photoelectric conversion element shown in Fig. 3 or Fig.
6 is a diagram showing a schematic configuration of a beam switching unit including a selection optical element for selectively distributing a beam from a light source device to one of six imaging units.
7 is a diagram showing a specific configuration around the optical element for selection and the incident mirror.
8 is a plan view of a polygon mirror of eight sides shown in Fig. 3 or Fig.
9 is a view for explaining a method of measuring the reproducibility (deviation) of the generation timing of the origin signal.
10 is a diagram schematically showing a method of predicting a time error due to a velocity fluctuation of a polygon mirror.
11 is a graph showing the results of measurement of the reproducibility of the origin signal generated corresponding to each of the reflection surfaces of the polygon mirror in the same manner as in Fig. 9 under predetermined conditions.
12 is a graph showing the results of measurement of the reproducibility of the origin signal generated corresponding to each of the reflection surfaces of the polygon mirror in the same manner as in Fig. 9 under the conditions different from those in Fig.
13 is a diagram showing a state in which a continuous pattern of five pixels in the main scanning direction is superimposed by superimposing the spot light for two pulses per pixel in the main scanning direction and the sub scanning direction at 1/2 of the spot size.
14 is a graph schematically showing a characteristic graph according to the actual example of Fig.
15 is a time chart for explaining the state of generation of the origin signal (correction origin signal) obtained by correcting the origin signal.
16 is a diagram showing an example of the configuration of a correction circuit (correction section) for generating a corrected origin signal (correction origin signal) by inputting the origin signal from the photoelectric conversion element, as shown in Fig.
17 is a diagram showing the configuration of the origin sensor according to the second modification.
18 is a diagram showing an example of a waveform of a photoelectric signal generated from a photodetector when a reference pattern in the form of a line and space formed on the outer circumferential surface of the rotary drum is scanned with spot light.
19 is a diagram showing an example of a circuit configuration for digitally sampling the waveform of a signal from the photodetector.
Fig. 20 is a time chart showing an example of measuring the deviation of the origin timing of the correction origin signal or the origin signal using the circuit configuration of Fig. 19; Fig.
21 is a diagram for explaining a method of test exposure for checking the accuracy of the correction origin signal (or the origin signal before correction) according to the third embodiment.
22 is a view showing a reference pattern in the form of a line continuous in the circumferential direction on the end portion of the outer circumferential surface of the rotary drum in the direction in which the central axis extends.
Fig. 23 is a partial sectional view of the rotary drum DR according to the fourth embodiment. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a beam scanning apparatus, a pattern writing apparatus, and a pattern drawing apparatus according to an aspect of the present invention will be described in detail with reference to the accompanying drawings. Further, aspects of the present invention are not limited to these embodiments, and various modifications or improvements may be added. In other words, the constituent elements described below include those that can be easily devised by those skilled in the art, and substantially the same elements can be appropriately combined. In addition, various omissions, substitutions or modifications of the constituent elements can be made without departing from the gist of the present invention.

[First Embodiment]

1 is a perspective view showing a schematic structure of an exposure apparatus (patterning device) EX for performing exposure processing on a substrate (object to be irradiated) P of the first embodiment. In the following description, unless otherwise specified, an XYZ orthogonal coordinate system in which the gravity direction is the Z direction is set, and the X direction, the Y direction, and the Z direction are described along the arrows in the drawing.

The exposure apparatus EX is a substrate processing apparatus used in a device manufacturing system for producing an electronic device by subjecting the substrate P to predetermined processing (such as exposure processing). The device manufacturing system includes, for example, a manufacturing system in which a manufacturing line for manufacturing a flexible display as an electronic device, a film-shaped touch panel, a film-like color filter for a liquid crystal display panel, a flexible wiring, to be. Hereinafter, a flexible display is assumed as an electronic device. Examples of the flexible display include an organic EL display, a liquid crystal display, and the like. The device manufacturing system is a system in which a substrate P is fed out from a feeding roll (not shown) in which a flexible (flexible) sheet-like substrate (sheet substrate) P is wound in a roll shape, Called roll-to-roll production system in which the substrate P after the various processes is wound up with a recovery roll (not shown). Therefore, the substrate P after the various processes is a substrate for multi-surface mounting in which a plurality of devices (display panels) are arranged in a state of being aligned in the transport direction of the substrate P. The substrate P supplied from the supply roll is sequentially subjected to various processes through the process apparatus of the previous process, the exposure apparatus EX and the process apparatus of the post-process, do. The substrate P has a band-like shape in which the moving direction (conveying direction) of the substrate P is long (long), and the width direction is short (long) Shape.

As the substrate P, for example, a resin film, a foil made of a metal such as stainless steel or an alloy, or the like is used. Examples of the material of the resin film include polyethylene resin, polypropylene resin, polyester resin, ethylene vinyl copolymer resin, polyvinyl chloride resin, cellulose resin, polyamide resin, polyimide resin, polycarbonate resin, Polystyrene resin, and vinyl acetate resin may be used. The thickness or rigidity (Young's modulus) of the substrate P is set such that when the substrate P passes through the transport path of the device manufacturing system or the exposure apparatus EX, the substrate P is folded by buckling or irreversible wrinkles It may be in a range that does not occur. Films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) having a thickness of about 25 mu m to 200 mu m as the base material of the substrate P are typical examples of suitable sheet substrates.

Since the substrate P is sometimes subjected to heat in each process performed in the device manufacturing system, it is preferable to select the substrate P having a material with a remarkably small thermal expansion coefficient. For example, the thermal expansion coefficient can be suppressed by mixing the inorganic filler with the resin film. The inorganic filler may be, for example, titanium oxide, zinc oxide, alumina, silicon oxide, or the like. Further, the substrate P may be a single-layered body made of a very thin glass having a thickness of about 100 占 퐉 manufactured by a float method or the like, and may be a laminate obtained by bonding the resin film, foil or the like to the ultra-violet glass.

By the way, the flexibility of the substrate P means a property that the substrate P can be warped without applying shearing force or breaking force to the substrate P even when a force of about its own weight is applied. Also, the property of bending by the force of the degree of self weight is included in the flexibility. The degree of flexibility varies depending on the material, size and thickness of the substrate P, the layer structure formed on the substrate P, the environment such as temperature or humidity, and the like. In any case, when the substrate P is correctly wound on the conveying direction switching member such as various conveying rollers, rotary drums, and the like provided in the conveying path in the device manufacturing system (exposure apparatus EX), the buckling and folding marks If the substrate P can be smoothly transported without causing breakage (breakage or cracking), it can be said to be within the range of flexibility.

The process apparatus (including a single processing section or a plurality of processing sections) of the previous process is a process in which the substrate P supplied from the supply roll is transported toward the exposure apparatus EX at a predetermined speed along the longitudinal direction , The processing of the previous step is performed on the substrate P supplied to the exposure apparatus EX. The substrate P supplied to the exposure apparatus EX by the processing of the previous step is a substrate (photosensitive substrate) having a photosensitive functional layer (photosensitive layer) formed on its surface.

This photosensitive functional layer is applied onto the substrate P as a solution and becomes a layer (film) by drying. A typical example of the photosensitive functional layer is a photoresist (liquid or dry film), but a photosensitive silane coupling agent (SAM) in which the hydrophilic property of a portion irradiated with ultraviolet rays is modified, And a photosensitive reducing agent in which a plating reduction unit is exposed at a portion irradiated with light. When a photosensitive silane coupling agent is used as the photosensitive functional layer, the pattern portion exposed by ultraviolet rays on the substrate P is modified from lyophobic to lyophilic. Therefore, by selectively applying a conductive ink (ink containing conductive nano particles such as silver or copper) or a liquid containing a semiconductor material on the lyophilic portion, electrodes constituting a thin film transistor (TFT) or the like, It is possible to form a pattern layer to be a wiring for semiconductor, insulation, or connection. When a photosensitive reductant is used as the photosensitive functional layer, a plating reductant is exposed to a pattern portion exposed by ultraviolet rays on the substrate P. Therefore, after the exposure, the substrate P is immediately immersed in the plating liquid containing palladium ions or the like for a predetermined time to form (precipitate) a pattern layer of palladium. Such a plating process is an additive process, but it may be premised on an etching process as a subtractive process. In this case, the substrate P to be supplied to the exposure apparatus EX can be made of PET or PEN, and a metallic thin film such as aluminum (Al) or copper (Cu) And then a photoresist layer is further laminated thereon.

The exposure apparatus (processing apparatus) EX is a device for transferring the substrate P transported from the process apparatus of the previous process to a process apparatus (including a single processing section or a plurality of processing sections) And performs exposure processing on the substrate P while being transported at a predetermined speed. The exposure apparatus EX is a device that applies a pattern for an electronic device (for example, a pattern of an electrode or a wiring of a TFT constituting an electronic device to a surface of the photosensitive functional layer, that is, a photosensitive surface) ) Is irradiated. As a result, a latent image (modified portion) corresponding to the pattern is formed on the photosensitive functional layer.

In the present embodiment, the exposure apparatus EX is an exposure apparatus of an intricate system that does not use a mask as shown in Fig. 1, that is, an exposure apparatus (imaging apparatus) of a so-called spot scanning system. The exposure apparatus EX includes a rotary drum DR for supporting the substrate P in the longitudinal direction for sub-scanning and a rotary drum DR for supporting the substrate P in the longitudinal direction by a portion of the substrate P supported by the rotary drum DR in a cylindrical surface shape Each of the plurality of drawing units Un (U1 to U6) includes a plurality of (six in this example) drawing units Un (U1 to U6) (Main scanning) the spot light SP of the light spot (pulse beam) on the surface to be irradiated (the photosensitive surface) of the substrate P in a predetermined scanning direction (Y direction) by a polygon mirror, (On / off) at a high speed according to pattern data (rendering data, pattern information). Thus, a light pattern corresponding to a predetermined pattern such as an electronic device, a circuit, or a wiring is drawn and exposed on the surface to be irradiated of the substrate P. That is, the spot light SP is relatively two-dimensionally scanned on the surface to be irradiated (the surface of the photosensitive functional layer) of the substrate P by the sub-scanning of the substrate P and the main scanning of the spot light SP, P, a predetermined pattern is drawn and exposed. Since the substrate P is conveyed along the longitudinal direction, a plurality of exposure regions in which the pattern is exposed by the exposure apparatus EX are provided at predetermined intervals along the longitudinal direction of the substrate P do. Since the electronic device is formed in this exposed region, the exposed region is also a device forming region.

1, the rotary drum DR includes a central axis AXo that extends in the Y direction and extends in a direction intersecting the direction in which gravity acts, and a central axis AXo extending in a cylindrical shape Respectively. The rotary drum DR rotates about the central axis AXo and rotates about the central axis AXo while curving and holding (maintaining) a part of the substrate P along the outer peripheral surface Of the substrate P onto which the beam LB (spot light SP) from each of the plurality of drawing units Un (U1 to U6) is projected is projected onto the rotary drum DR (Portion) is supported by its outer circumferential surface. The rotary drum DR supports (holds and maintains) the substrate P from the side (back side) opposite to the side (side on which the photosensitive surface is formed) on which the electronic device is formed. Shafts (not shown) are provided on both sides of the rotary drum DR in the Y direction so as to be supported by the bearings so as to rotate the rotary drum DR around the central axis AXo. A rotational torque is applied from a rotation drive source (not shown) (for example, a motor or a deceleration mechanism) to the shaft, and the rotary drum DR rotates around the central axis AXo at a constant rotation speed.

The light source device (pulse light source device) LS generates and emits a pulse beam (pulse beam, pulse light, laser) LB. This beam LB is ultraviolet light having sensitivity to the photosensitive layer of the substrate P and having a peak wavelength in a wavelength band of 370 nm or less. The light source device LS emits and emits a pulse-shaped beam LB at a frequency (oscillation frequency, predetermined frequency) Fa under the control of a drawing control device not shown here. This light source device LS includes a semiconductor laser device for generating pulse light in the infrared wavelength range, a fiber amplifier, and a wavelength conversion element (harmonic generation element) for converting pulsed light in the amplified infrared wavelength range into pulse light in the ultraviolet wavelength range, And the like are used as a fiber amplifier laser light source. By constituting the light source device LS as described above, ultraviolet pulse light having an oscillation frequency Fa of several hundreds of MHz and a high luminance of less than several tens of picoseconds can be obtained. It is also assumed that the beam LB emitted from the light source LS is a narrow parallel beam whose beam diameter is about 1 mm or less. The configuration in which the light source unit LS is used as a fiber amplifier laser light source and pulses of the beam LB are turned on / off at a high speed in accordance with the state of the pixels constituting the rendering data ("0" or "1" Is disclosed in International Publication No. 2015/166910 pamphlet.

The beam LB emitted from the light source device LS includes optical elements OSn (OS1 to OS6) as a plurality of switching elements, a plurality of reflection mirrors M1 to M12, a plurality of incident mirrors IMn (U1 to U6) via a beam switching unit constituted by a plurality of imaging units (IM1 to IM6) and an absorber (TR). The optical elements OSn (OS1 to OS6) for selection have transmissivity with respect to the beam LB and are driven by an ultrasonic signal to deflect the first-order diffracted light of the incident beam LB at a predetermined angle, And an acousto-optic modulator (AOM). A plurality of selection optical elements OSn and a plurality of incident mirrors IMn are provided corresponding to each of the plurality of imaging units Un. For example, the selection optical element OS1 and the entrance mirror IM1 are provided corresponding to the imaging unit U1, and similarly, the selection optical elements OS2 to OS6 and the entrance mirrors IM2 to IM6, Are provided corresponding to the rendering units U2 to U6, respectively.

The beam LB from the light source LS is deflected into a sinuous shape by the reflecting mirrors M1 to M12 and guided to the absorber TR. Hereinafter, the case in which all of the optical elements for selection OSn (OS1 to OS6) are in an off state (state in which no ultrasonic signal is applied and first order diffracted light is not generated) will be described in detail. Although not shown in Fig. 1, a plurality of lenses are provided in the beam path from the reflecting mirror M1 to the absorber TR, and the plurality of lenses converge or converge the beam LB from the parallel beams, The beam LB is returned to the parallel beam. The constitution will be described below with reference to FIG.

1, the beam LB from the light source LS travels in the -X direction parallel to the X axis and enters the reflecting mirror M1. The beam LB reflected from the reflecting mirror M1 in the -Y direction enters the reflecting mirror M2. The beam LB reflected from the reflecting mirror M2 in the + X direction is transmitted straight through the optical element OS5 to reach the reflecting mirror M3. The beam LB reflected from the reflecting mirror M3 in the -Y direction enters the reflecting mirror M4. The beam LB reflected from the reflecting mirror M4 in the -X direction is transmitted straight through the optical element for selection OS6 and reaches the reflecting mirror M5. The beam LB reflected from the reflecting mirror M5 in the -Y direction enters the reflecting mirror M6. The beam LB reflected from the reflecting mirror M6 in the + X direction passes straight through the optical element for selection OS3 and reaches the reflecting mirror M7. The beam LB reflected from the reflecting mirror M7 in the -Y direction enters the reflecting mirror M8. The beam LB reflected from the reflecting mirror M8 in the -X direction is transmitted straight through the optical element OS4 to reach the reflecting mirror M9. The beam LB reflected from the reflecting mirror M9 in the -Y direction enters the reflecting mirror M10. The beam LB reflected from the reflecting mirror M10 in the + X direction passes straight through the optical element OS1 to reach the reflecting mirror M11. The beam LB reflected from the reflecting mirror M11 in the -Y direction enters the reflecting mirror M12. The beam LB reflected from the reflecting mirror M12 in the -X direction passes straight through the optical element for selection OS2 and is guided to the absorber TR. The absorber TR is a light trap that absorbs the beam LB to suppress leakage of the beam LB to the outside.

When each of the optical elements OSn is applied with an ultrasonic signal (high-frequency signal), the first-order diffracted light obtained by diffracting the incident beam (zero-order light) LB at a diffraction angle corresponding to the frequency of the high- (Beam LBn). Therefore, the beam emitted as the first-order diffracted light from the optical element OS1 becomes the LB1, and the beams emitted as the first-order diffracted light from the selection optical elements OS2 to OS6 become the beams LB2 to LB6. Thus, each of the selection optical elements OSn (OS1 to OS6) exerts the function of deflecting the optical path of the beam LB from the light source device LS. However, in the actual acoustooptic modulator, since the generation efficiency of the 1st-order diffracted light is about 80% of the 0th order light, the beams LBn (LB1 to LB6) deflected by each of the selection optical elements OSn are the original Which is lower than the intensity of the beam LB. In the present embodiment, it is controlled by a drawing control device (not shown) so that only one selected optical element OSn (OS1 to OS6) is turned on for a predetermined time. When the selected one optical element OSn is in the ON state, about 0% of the zero-order light which is not diffracted by the optical element OSn for selection but remains straight is left by the absorber TR Absorbed.

Each of the optical elements OSn is provided so as to deflect the beams LBn (LB1 to LB6), which are deflected first-order diffracted light, in the -Z direction with respect to the incident beam LB. The beams LBn (LB1 to LB6) deflected and emitted by the respective optical elements OSn are incident on the incident mirrors IMn (IM1 to IM6) provided at positions separated from the respective optical elements OSn by a predetermined distance, . Each of the incident mirrors IMn reflects the incident beams LBn (LB1 to LB6) in the -Z direction so that the beams LBn (LB1 to LB6) correspond to the corresponding imaging units Un (U1 to U6) .

The same configuration, function, action, and the like of each optical element OSn may be used. Each of the plurality of selection optical elements OSn turns on / off the generation of the diffracted light by diffracting the incident beam LB in accordance with on / off of the drive signal (the ultrasonic signal) from the painting controller. For example, the optical element OS5 does not diffract the beam LB from the incident light source LS when the driving signal (high-frequency signal) from the imaging controller is not applied and is in the OFF state Lt; / RTI > Therefore, the beam LB transmitted through the selection optical element OS5 enters the reflecting mirror M3. On the other hand, when the selection optical element OS5 is in the ON state, the incident beam LB is diffracted to be directed to the incident mirror IM5. That is, switching (beam selection) operation by the optical element OS5 is controlled by on / off of the driving signal. In this manner, the beam LB from the light source unit LS can be guided to any one drawing unit Un by the switching operation of the optical element OSn for selection, and the beam LBn It is possible to switch the drawing unit Un to which this image is incident. As described above, a plurality of optical elements for selection OSn are arranged in series with respect to the beam LB from the light source unit LS, and the beam LBn is supplied to the corresponding drawing unit Un in a time- Is disclosed in International Publication No. 2015/166910 pamphlet.

The order in which each of the optical elements for selection OSn (OS1 to OS6) constituting the beam switching unit is turned on for a predetermined time is, for example, OS1? OS2? OS3? OS4? OS5? OS6? OS1? As shown in Fig. This sequence number is determined by the sequence number of the scanning start timing by the spot light set in each of the rendering units Un (U1 to U6). That is, in this embodiment, the phase of the rotation angle is synchronized with the rotation speed of the polygon mirror provided in each of the six drawing units U1 to U6, so that any one of the drawing units U1 to U6 It is possible to switch to a time division so that one reflection surface of the polygon mirror in the projection optical system 1 performs one spot scan on the substrate P. Therefore, if the phases of the rotation angles of the polygonal mirrors of the drawing units Un are synchronized in a predetermined relation, the order of spot scanning of the drawing unit Un may be any. 1, three drawing units U1, U3 and U5 are arranged in the Y direction on the upstream side in the carrying direction of the substrate P (the direction in which the outer peripheral surface of the rotary drum DR moves in the peripheral direction) And three drawing units U2, U4, U6 are arranged in the Y direction on the downstream side in the carrying direction of the substrate P.

In this case, the patterning operation on the substrate P is started from the odd number drawing units U1, U3 and U5 on the upstream side, and when the substrate P is sent to a certain length, the even number of drawing units U2 , U4, and U6 also start pattern drawing, the order of spot scanning of the drawing unit (Un) is changed from U1 to U3 to U5 to U2 to U4 to U6 to U1 to U6. . Therefore, the order in which each of the optical elements OSn (OS1 to OS6) is turned on for a predetermined time is OS1? OS3? OS5? OS2? OS4? OS6? OS1? . Also, even when the selection optical element OSn corresponding to the drawing unit Un having no pattern to be drawn has an ON state, the on / off switching control of the selection optical element OSn is performed based on the drawing data The spot scanning by the imaging unit Un is not carried out because it is forcibly kept in the off state.

As shown in Fig. 1, each of the imaging units U1 to U6 is provided with a polygon mirror PM for main scanning the incident on beams LB1 to LB6. In this embodiment, the polygon mirrors PM of the drawing units Un are synchronously controlled so as to maintain a constant rotation angle phase with each other while being precisely rotated at the same rotation speed. This makes it possible to set the timing of main scanning (the main scanning period of spot light SP) of each of the beams LB1 to LB6 projected onto the substrate P from each of the rendering units U1 to U6 so as not to overlap each other . Therefore, the ON / OFF switching of each of the optical elements OS1 (OS1 to OS6) provided in the beam switching unit is controlled in synchronization with the rotation angle position of each of the six polygon mirrors PM, Can be efficiently distributed to the plurality of imaging units (Un) in a time-division manner.

Synchronous control of the phase alignment of the rotation angles of the six polygon mirrors PM and the on / off switching timings of the optical elements OSn (OS1 to OS6), respectively, is described in the pamphlet of International Publication No. 2015/166910 However, in the case of the eight-sided polygon mirror PM, about 1/3 of the rotation angle (45 degrees) of one reflection plane as the scanning efficiency is about 1/3 of the spot light SP on the drawing line SLn The polygon mirror PM rotates the six polygon mirrors PM by 15 degrees at a relatively slower rotation angle, and the polygon mirror PM reflects the beam LBn by skipping one of the eight reflecting surfaces. The switching of on / off of each of the optical elements OSn (OS1 to OS6) for selection is controlled. As described above, the drawing method using the one-plane skipping of the reflection surface of the polygon mirror PM is also disclosed in International Publication No. 2015/166910 pamphlet.

As shown in Fig. 1, the exposure apparatus EX is a so-called multi-head type linear exposure method in which a plurality of imaging units Un (U1 to U6) having the same configuration are arranged. Each of the drawing units Un draws a pattern for each partial area partitioned by the Y direction of the substrate P supported by the outer circumferential surface (circumferential surface) of the rotary drum DR. Each of the rendering units Un (U1 to U6) projects the beam LBn from the beam switching unit onto the substrate P (on the surface to be irradiated on the substrate P) (Convergence). As a result, the beams LBn (LB1 to LB6) projected onto the substrate P become spot lights SP. The spot light SP of the beams LBn (LB1 to LB6) projected onto the substrate P is rotated in the main scanning direction (Y direction) by the rotation of the polygon mirror PM of each drawing unit Un Is injected. Linear scanning lines SLn (n = 1, 2, ..., 6 (scanning lines)) for drawing a pattern for one line are formed on the substrate P by the scanning of the spot light SP ) Is defined. The drawing line SLn is also a scanning locus on the substrate P of the spot light SP of the beam LBn.

The drawing unit U1 scans the spot light SP along the drawing line SL1 and similarly the drawing units U2 to U6 scan the spot light SP along the drawing lines SL2 to SL6 . 1, the drawing lines SLn (SL1 to SL6) of the plurality of drawing units Un (U1 to U6) include the central axis AXo of the rotary drum DR and are parallel to the YZ plane And arranged in a zigzag arrangement in two rows in the circumferential direction of the rotary drum DR with a central plane interposed therebetween. The odd number of drawing lines SL1, SL3 and SL5 are located on the surface to be processed of the substrate P on the upstream side (-X direction side) in the carrying direction of the substrate P with respect to the center plane, Therefore, they are arranged in one row apart by a predetermined interval. The even number of drawing lines SL2, SL4 and SL6 are located on the surface to be processed of the substrate P on the downstream side (+ X direction side) in the carrying direction of the substrate P with respect to the center plane, Therefore, they are arranged in one row apart by a predetermined interval. Therefore, the plurality of drawing units Un (U1 to U6) are also arranged in two rows in the zigzag arrangement in the conveying direction of the substrate P with the center plane therebetween, and the odd number drawing units U1, U3, And the imaging units U2, U4 and U6 in an even number are provided symmetrically with respect to the central plane in the XZ plane.

The odd number of drawing lines SL1, SL3 and SL5 and the even number of drawing lines SL2, SL4 and SL6 are separated from each other in the X direction (conveying direction of the substrate P) The width direction of the substrate P, and the main scanning direction) are set so as not to be separated from each other. The drawing lines SL1 to SL6 are substantially parallel to the width direction of the substrate P, that is, the central axis AXo of the rotary drum DR. The fact that the drawing lines SLn are aligned in the Y direction means that the positions in the Y direction of the end portions of the drawing line SLn are adjacent or partially overlapped. In the case of overlapping the end portions of the drawing line SLn, for example, if the length of each drawing line SLn is overlapped within a range of several% or less in the Y direction including the drawing start point or the drawing end point good.

As described above, the plurality of drawing units Un (U1 to U6) share the Y-direction scanning area (section of the main scanning range) so as to cover the widthwise dimension of the exposure area on the substrate P by all have. For example, when the Y main-scan range (the length of the drawing line SLn) by the single drawing unit Un is about 30 to 60 mm, a total of six drawing units U1 to U6 are arranged in the Y direction , The width of the imageable exposure region in the Y direction is widened to about 180 to 360 mm. The length of each drawing line SLn (SL1 to SL6) (the length of the drawing range) is, in principle, the same. That is, the scanning distance of the spot light SP of the beam LBn scanned along each of the rendering lines SL1 to SL6 is, in principle, the same.

In the case of the present embodiment, when the beam LB from the light source LS is pulse light with a light emission time of several tens of picoseconds or less, the spot light SP projected onto the imaging line SLn during main scanning, (For example, 400 MHz) of the oscillation frequency LB. Therefore, it is necessary to overlap the spot light SP projected by the one pulse light of the beam LB and the spot light SP projected by the next one pulse light in the main scanning direction. The overlap amount is set by the size? Of the spot light SP, the scanning speed (main scanning speed) Vs of the spot light SP, and the oscillation frequency Fa of the beam LB. The effective size (diameter)? Of the spot light SP is 1 / e ² (or 1/2) of the peak intensity of the spot light SP when the intensity distribution of the spot light SP is approximated by a Gaussian distribution. Is the width dimension which is the strength of the projections. In the present embodiment, the scanning speed Vs of the spot light SP (the rotation speed of the polygon mirror PM) and the scanning speed Vs of the spot light SP are adjusted so that the spot light SP is approximately overlapped with the effective size (dimension) The oscillation frequency Fa is set. Therefore, the projection interval of the pulse-like spot light SP along the main-scan direction becomes? / 2. Therefore, also in regard to the sub-scanning direction (the direction orthogonal to the drawing line SLn), between the scanning of the spot light SP along the drawing line SLn and the next scanning, Is set to move by a distance of about 1/2 of the effective size? Of the spot light SP. Also, in the case of connecting the drawing lines SLn adjacent to each other in the Y direction in the main scanning direction, it is also preferable to overlap the drawing lines SLn by? / 2. In the present embodiment, the size (dimension)? Of the spot light SP is set to about 3 to 4 占 퐉.

Each of the rendering units Un (U1 to U6) is set such that each beam LBn advances toward the central axis AXo of the rotary drum DR when viewed in the XZ plane. Thus, the optical path (beam main ray) of the beam LBn proceeding from the respective imaging units Un (U1 to U6) toward the substrate P is shifted in the XZ plane by the normal line of the irradiated surface of the substrate P . The beam LBn irradiated from each of the rendering units Un (U1 to U6) to the rendering lines SLn (SL1 to SL6) is formed on the surface of the substrate P curved in a cylindrical surface, , The light is projected toward the substrate P so as to be always perpendicular to the tangent plane. That is, with respect to the main scanning direction of the spot light SP, the beams LBn (LB1 to LB6) projected onto the substrate P are scanned in a telecentric state.

Since the imaging unit (beam scanning device) Un shown in FIG. 1 has the same configuration, only the imaging unit U1 will be described briefly. The detailed configuration of the rendering unit U1 will be described below with reference to FIG. The drawing unit U1 includes at least the reflecting mirrors M20 to M24, the polygon mirror PM and the f? Lens system (drawing scanning lens) FT. Although not shown in Fig. 1, a first cylindrical lens CYa (see Fig. 2) is disposed immediately before the polygon mirror PM as viewed in the traveling direction of the beam LB1, and an f lens system f -θ lens system) FT, a second cylindrical lens CYb (see FIG. 2) is provided. The spotlights SP (imaging line SL1) due to the tilting error of the respective reflective surfaces of the polygon mirror PM are formed by the first and second cylindrical lenses CYa and CYb, ) In the sub-scan direction is corrected.

The beam LB1 reflected in the -Z direction in the incident mirror IM1 is incident on the reflecting mirror M20 provided in the imaging unit U1 and the beam LB1 reflected on the reflecting mirror M20 is reflected by the reflecting mirror M20, Advances in the X direction and enters the reflection mirror M21. The beam LB1 reflected by the reflecting mirror M21 in the -Z direction is incident on the reflecting mirror M22 and the beam LB1 reflected by the reflecting mirror M22 travels in the + M23. The reflecting mirror M23 reflects the incident beam LB1 toward the reflecting surface RP of the polygon mirror PM so as to bend in a plane parallel to the XY plane.

The polygon mirror PM reflects the incident beam LB1 toward the +? Direction toward the f? Lens system FT. The polygon mirror PM deflects the incident beam LB1 in one dimension within a plane parallel to the XY plane so as to scan the spot light SP of the beam LB1 on the surface to be irradiated on the substrate P. Reflection). Specifically, the polygon mirror (rotary polygon mirror, movable deflection member) PM includes a rotation axis AXp extending in the Z-axis direction and a plurality of reflection surfaces RP formed around the rotation axis AXp The number Np of reflecting surfaces RP is 8). By rotating the polygon mirror PM in the predetermined rotation direction around the rotation axis AXp, the reflection angle of the pulse-like beam LB1 irradiated on the reflection surface can be continuously changed. As a result, the beam LB1 is deflected by one reflecting surface RP and the spot light SP of the beam LB1 irradiated onto the surface to be irradiated on the substrate P is irradiated in the main scanning direction (the substrate P) In the width direction, Y direction). The number of the imaging lines SL1 in which the spot light SP is scanned on the surface to be irradiated on the substrate P by one rotation of the polygon mirror PM is maximized by the number of the reflecting surfaces RP The same eight.

θ/2)에 따라 변화한다. fθ 렌즈계(FT)는, 반사 미러(M24)를 거쳐, 그 입사각 θ에 비례한 기판(P)의 피조사면 상의 상고(像高) 위치에 빔(LB1)을 투사한다. fθ 렌즈계(FT)의 초점 거리를 fo로 하고, 상고 위치를 yo로 하면, fθ 렌즈계(FT)는, yo = fo×θ의 관계(왜곡 수차)를 만족하도록 설계되어 있다. 따라서, 이 fθ 렌즈계(FT)에 의해서, 빔(LB1)을 Y방향으로 정확하게 등속으로 주사하는 것이 가능하게 된다. 또한 fθ 렌즈계(FT)에 입사하는 빔(LB1)이 폴리곤 미러(PM)에 의해서 1차원으로 편향되는 면(XY면과 평행)은, fθ 렌즈계(FT)의 광축(AXf)을 포함하는 면이 된다.The f? lens system (scanning lens, scanning optical system) FT is a telecentric scanning lens for projecting the beam LB1 reflected by the polygon mirror PM onto the reflection mirror M24. The beam LB1 transmitted through the f? lens system FT is projected onto the substrate P via the reflection mirror M24 as spot light SP. At this time, the reflection mirror M24 reflects the beam LB1 toward the substrate P so that the beam LB1 advances toward the central axis AXo of the rotary drum DR with respect to the XZ plane. The incident angle? Of the beam LB1 to the f? Lens system FT is the angle of incidence of the polygon mirror PM

/ 2). The f? lens system FT projects the beam LB1 through the reflection mirror M24 to an image height position on the surface to be irradiated of the substrate P proportional to the incident angle?. When the focal length of the f? lens system FT is fo and the image height is yo, the f? lens system FT is designed to satisfy the relationship yo = fo x? (distortion aberration). Therefore, it is possible to accurately scan the beam LB1 in the Y direction at the constant velocity by the f? Lens system FT. The plane (parallel to the XY plane) where the beam LB1 incident on the f? Lens system FT is one-dimensionally deflected by the polygon mirror PM is a plane including the optical axis AXf of the f? do.

Next, the optical configuration of the imaging units Un (U1 to U6) will be described with reference to Fig. 2, in the drawing unit Un, there are disposed a reflection mirror M20, a reflection mirror M20, and a reflection mirror M20 along the traveling direction of the beam LBn from the incident position of the beam LBn to the surface to be irradiated (substrate P) A mirror M20a, a polarization beam splitter BS1, a reflection mirror M21, a reflection mirror M22, a first cylindrical lens CYa, a reflection mirror M23, a polygon mirror PM, an f? Lens system FT A reflecting mirror M24, and a second cylindrical lens CYb. The imaging unit Un also detects the angular position of each reflection surface of the polygon mirror PM in order to detect the imaging start timing (scanning start timing of the spotlight SP) of the imaging unit Un A beam transmitting system 60a and a beam receiving system 60b as an origin detecting sensor (origin detector) are provided. In the drawing unit Un, reflected light of the beam LBn reflected by the surface to be irradiated (or the surface of the rotary drum DR) of the substrate P is reflected by the f? Lens system FT, the polygon mirror PM, And a photodetector DTc for detection via a polarization beam splitter BS1 or the like is provided.

The beam LBn incident on the imaging unit Un travels in the -Z direction along the optical axis AX1 parallel to the Z axis and enters the reflecting mirror M20 tilted by 45 degrees with respect to the XY plane. The beam LBn reflected by the reflecting mirror M20 advances in the -X direction toward the reflecting mirror M20a which is away from the reflecting mirror M20 in the -X direction. The reflecting mirror M20a is disposed at an angle of 45 占 with respect to the YZ plane, and reflects the incident beam LBn toward the polarization beam splitter BS1 in the -Y direction. The polarization splitting surface of the polarized beam splitter BS1 is disposed at an angle of 45 DEG with respect to the YZ plane, and reflects a beam of P polarized light and transmits a beam of linearly polarized light (S polarized light) polarized in a direction orthogonal to the P polarized light . When the beam LBn incident on the imaging unit Un is a beam of P polarized light, the polarizing beam splitter BS1 reflects the beam LBn from the reflecting mirror M20a in the -X direction to form the reflecting mirror M21 . The reflecting mirror M21 is disposed at an angle of 45 占 with respect to the XY plane and reflects the incident beam LBn toward the reflecting mirror M22 away from the reflecting mirror M21 in the -Z direction in the -Z direction. The beam LBn reflected by the reflection mirror M21 is incident on the reflection mirror M22. The reflecting mirror M22 is disposed at an angle of 45 DEG with respect to the XY plane, and reflects the incident beam LBn toward the reflecting mirror M23 in the + X direction. The beam LBn reflected by the reflection mirror M22 is incident on the reflection mirror M23 via the? / 4 wave plate (not shown) and the cylindrical lens CYa. The reflecting mirror M23 reflects the incident beam LBn toward the polygon mirror PM.

The polygon mirror PM reflects the incident beam LBn toward the + X direction toward the f? Lens system FT having the optical axis AXf parallel to the X axis. The polygon mirror PM deflects the incident beam LBn in one dimension within a plane parallel to the XY plane in order to scan the spot light SP of the beam LBn on the surface to be irradiated on the substrate P. Reflection). The polygon mirror PM has a plurality of reflection surfaces (each side of a regular octagon in the present embodiment) formed around the rotation axis AXp extending in the Z-axis direction and a rotation motor RM coaxial with the rotation axis AXp. . The rotation motor RM is rotated at a constant rotation speed (for example, about 30,000 to 40,000 rpm) by a drawing control device not shown. As described above, the effective length (for example, 50 mm) of the drawing lines SLn (SL1 to SL6) is the maximum scanning length (the maximum scanning length) at which the spot light SP can be scanned by the polygon mirror PM (Optical axis AXf of the f? Lens system FT) passes through the center of the imaging line SLn at the center of the maximum scanning length Is set.

The cylindrical lens CYa conveys the incident beam LBn to the reflection surface of the polygon mirror PM with respect to the sub scanning direction (Z direction) orthogonal to the main scanning direction (rotation direction) Lt; / RTI > That is, the cylindrical lens CYa converges the beam LBn on the reflection surface of the polygon mirror PM into a slit shape (long elliptic shape) extending in a direction parallel to the XY plane. Even if the reflecting surface of the polygon mirror PM is inclined from a state parallel to the Z axis by the cylindrical lens CYa whose busbars are parallel to the Y direction and the cylindrical lens CYb described below , The irradiation position of the beam LBn (drawing line SLn) irradiated on the surface to be irradiated on the substrate P can be suppressed from shifting in the sub-scanning direction.

The incident angle? (Angle with respect to the optical axis AXf) of the beam LBn to the f? Lens system FT changes in accordance with the rotation angle? / 2 of the polygon mirror PM. When the incident angle? Of the beam LBn to the f? Lens system FT is 0 degree, the beam LBn incident on the f? Lens system FT travels along the optical axis AXf. The beam LBn from the f? lens system FT is reflected in the -Z direction by the reflection mirror M24 and is projected toward the substrate P via the cylindrical lens CYb. the beam LBn projected onto the substrate P by the f? lens system FT and the cylindrical lens CYb whose busbars are parallel to the Y direction is projected on the surface to be processed of the substrate P Converging to a minute spot light SP of 2 to 3 mu m. As described above, the beam LBn incident on the imaging unit Un is bent along the optical path cranked in a U-shape from the reflecting mirror M20 to the substrate P as viewed in the XZ plane, and the beam Z And is projected onto the substrate P. Each of the six drawing units U1 to U6 transports the substrate P in the longitudinal direction while scanning each spot light SP of the beams LB1 to LB6 in one direction in the main scanning direction Y direction, The surface to be inspected of the substrate P is relatively two-dimensionally scanned by the spotlight SP and a pattern drawn by each of the imaging lines SL1 to SL6 is exposed on the substrate P in a state of being aligned in the Y direction .

The effective scanning length LT of the imaging lines SLn (SL1 to SL6) is 50 mm, the effective diameter of the spot light SP is 4 m, and the pulse light emission of the beam LB from the light source device LS When the oscillation frequency Fa of the spot light SP is 400 MHz and the spot light SP is pulse-emitted so as to overlap each other by 1/2 of the diameter? Along the drawing line SLn (main scanning direction) Direction is 2 mu m on the substrate P, which corresponds to 2.5 nS (1/400 MHz), which is the period Tf (= 1 / Fa) of the oscillation frequency Fa. In this case, the pixel size Pxy specified on the rendering data is set to 4 占 퐉 (one-side length of a square or a rectangle) on the substrate P, and one pixel has the spot light SP). Therefore, the scanning speed Vsp in the main scanning direction of the spotlight SP and the oscillation frequency Fa are set to be Vsp = (φ / 2) / Tf. On the other hand, the scanning speed Vsp is determined based on the rotation speed VR (rpm) of the polygon mirror PM, the effective scanning length LT and. On the basis of the number Np (= 8) of reflecting surfaces of the polygon mirror PM and the scanning efficiency 1 /? By one reflecting surface RP of the polygon mirror PM.

Vsp = (8?? VR? LT) / 60 [mm / sec]

Therefore, the oscillation frequency Fa and the rotation speed VR (rpm) are set to be the following relationship.

(? / 2) / Tf = (8?? VR? LT) / 60 ... Equation (1)

The scanning speed Vsp defined by the oscillation frequency Fa is 0.8 m / nS (= 2 m / 2.5 ns) when the oscillation frequency Fa is 400 MHz (Tf = 2.5 nS) and the diameter? Of the spot light SP is 4 m. . In order to correspond to the scanning speed Vsp, the rotation of the polygon mirror PM on the eight sides from the relation of the expression (1) when the scanning efficiency 1 /? Is 0.3 (? 3.33) and the scanning length LT is 50 mm, The speed VR may be set to 36000 rpm. In this case, the scanning speed Vsp = 0.8 mu m / nS is 2880 Km / h in terms of the speed. As described above, when the scanning speed Vsp becomes high, it is necessary to increase the reproducibility of the generation timing of the origin signal from the origin sensor (the beam emitting system 60a and the beam receiving system 60b) that determines the pattern drawing start timing . For example, assuming that the size of one pixel is 4 占 퐉 and the minimum dimension (minimum line width) of the pattern to be drawn is 8 占 퐉 (two pixels), a new pattern is formed on the pattern already formed on the substrate P The overlapping accuracy (range of allowable position error) at the time of the second exposure to be overlapped and exposed needs to be about 1/4 to 1/5 of the minimum line width. That is, when the minimum line width is 8 占 퐉, the allowable range of the position error is 2 占 퐉 to 1.6 占 퐉. This value is equal to or smaller than the interval of two pulses of the spot light SP corresponding to the oscillation period Tf (2.5 nS) of the beam LB from the light source LS and corresponds to one pulse of the spot light SP Which means that no error is allowed. For this reason, it is necessary to set the reproducibility of the generation timing of the origin signal for determining the pattern drawing start timing (start position) to a period Tf (2.5 nS) or less.

The beam receiving system 60b constituting the origin detecting sensor (hereinafter also simply referred to as the origin sensor) shown in Fig. 2 is arranged such that the rotational position of the reflecting surface RP of the polygon mirror PM is the reflecting surface RP, The origin signal SZn is generated when it comes to a predetermined position just before the start of the scanning of the spot beam SP of the imaging beam LBn by the beam spot LBn. Since the polygon mirror PM has eight reflecting surfaces RP, the beam receiving system 60b outputs eight origin signals SZn during one rotation of the polygon mirror PM. The origin signal SZn is sent to a drawing control device (not shown), and after the origin signal SZn has elapsed, a predetermined delay time Tdn has elapsed. Thereafter, the origin signal SZn is scanned along the drawing line SLn of the spotlight SP Lt; / RTI >

3 is a diagram showing the arrangement of the beam receiving system 60b constituting the polygon mirror PM, the f? Lens system FT and the origin sensor (the origin detector of the light) in the imaging unit Un, FIG. 3, the laser beam Bga is projected from the beam transmission system 60a toward one reflective surface RPa of the reflective surface RP of the polygon mirror PM, Represents the angle state of the reflecting surface RPa at the instant when the spot beam SP of the usable beam LBn is positioned at the drawing start point of the drawing line SLn. Here, the reflecting surface RP (RPa) of the polygon mirror PM is arranged so as to be located at the entrance pupil surface orthogonal to the optical axis AXf of the f? Lens system FT. Strictly speaking, at the angular position of the instantaneous reflecting surface RP (RPa) where the principal ray of the beam LBn incident on the f? Lens system FT is coaxial with the optical axis AXf, the reflecting mirror M23 (RP (RPa)) is set at a position where the principal ray of the beam LBn directed from the polygon mirror PM to the polygon mirror PM crosses the optical axis AXf. The distance from the main surface of the f? Lens system FT to the surface of the substrate P (light-converging point of the spot light SP) is the focal length fo.

The laser beam Bga is projected onto the reflective surface RPa as a parallel light flux in the non-photosensitive wavelength range with respect to the photosensitive functional layer of the substrate P. [ Although the reflected beam Bgb of the laser beam Bga reflected from the reflecting surface RPa is directed to the direction of the f? Lens system FT in the state of Fig. 3, The reflective beam Bbb is incident on the lens system (optical element) GLb constituting the beam receiving system 60b and reflected by the reflective mirror Mb And reaches the photoelectric conversion element (photoelectric detector) DTo. The reflected beam Bgb (parallel light flux) is condensed as a spot light SPr on the light receiving surface of the photoelectric conversion element DTo by the lens system GLb and the reflected beam Bgb is incident on the lens system GLb The spot light SPr is scanned so as to traverse the light receiving surface of the photoelectric conversion element DTo with the rotation of the polygon mirror PM and the photoelectric conversion element (narrow origin detector) DTo is scanned to the origin signal SZn. In this embodiment, in order to enhance the reproducibility of the timing of generation of the origin signal SZn, the scanning speed Vsp of the spot beam SP of the drawing beam LBn on the substrate P is set to be smaller than the scanning speed Vsp The focal length of the lens system GLb is made larger than the focal length fo of the f? Lens system FT so as to increase the scanning speed of the spotlight SPr on the photoelectric conversion element DTo.

4 is a view showing a simplified arrangement of the beam transmission system 60a and the beam reception system 60b shown in Figs. 2 and 3. The beam transmission system 60a includes a laser beam Bga And a collimator lens (lens system) GLa that collimates the beam Bga from the light source to a semiconductor laser light source LDo that continuously emits light (also referred to as a beam Bga). The beam Bga projected onto the reflecting surface RP (RPa) is reflected by the reflecting surface RP (RPa) in order to stably detect the change in angle of the reflecting surface RP (RPa) of the polygon mirror PM with high accuracy, (The main-scan direction parallel to the XY plane), the parallel light flux having a certain width is obtained. On the other hand, in the beam receiving system 60b, it is preferable that the reflected beam Bgb is condensed on the photoelectric conversion element DTo with the spot light SPr narrowed narrow in the main scanning direction. Therefore, the lens system GLb having the focal length Fgs is provided. The distance from the reflecting surface RP (RPa) of the polygon mirror PM to the lens system GLb can be set relatively freely since the reflected beam Bgb becomes a parallel beam. The light receiving surface of the photoelectric conversion element DTo is disposed at the position of the focal length Fgs on the rear side of the lens system GLb. When the reflected beam Bgb reflected by the reflecting surface RP (RPa) is incident coaxially with the optical axis of the lens system GLb, the spotlight SPr of the reflected beam Bgb is received by the photoelectric conversion element DTo Is set to be located almost at the center of the plane.

Even when the reflected beam Bgb 'slightly inclined in the main scanning direction is incident on the optical axis of the lens system GLb, the reflected beam Bgb' is incident on the optical axis of the spot light (SPr) and is condensed. The reflected beam Bgb 'directed from the lens system GLb to the photoelectric conversion element DTo does not need to be telecentric but needs to be set so that the speed of the spot light SPr traversing the light receiving surface of the photoelectric conversion element DTo is To be high, it is rather non - telecentric. As described above, by setting the focal length Fgs of the lens system GLb and the focal length fo of the f? Lens system FT to Fgs> fo, it is possible to determine the timing of generation of the origin signal SZn output from the photoelectric conversion element DTo Reproducibility (accuracy) can be increased. The method of obtaining the reproducibility of the origin signal SZn and the degree of improvement of the reproducibility will be described later.

Fig. 5 shows a detailed configuration of the photoelectric conversion element DTo. In the present embodiment, for example, S9684 series sold by Hamamatsu Portix Co., Ltd. is used as a photo IC for laser beam synchronization detection. As shown in Fig. 5, the photo IC includes light receiving surfaces PD1 and PD2 of two PIN photodiodes arranged in a narrow gap (dead band) in the scanning direction of the spot light SPr, IC1 and IC2, and a comparator IC3 are packaged in a single package. When the spot light SPr traverses the light receiving surfaces PD1 and PD2 in this order, each of the current amplifying units IC1 and IC2 generates the output signals STa and STb as shown in Fig. 5A . A constant offset voltage (reference voltage) Vref is applied to the current amplification section IC1 for amplifying the photocurrent from the light receiving surface PD1 receiving the spotlight SPr for the first time, The photodiode STa is biased to be the reference voltage Vref when the photocurrent generated on the light-receiving surface PD1 is zero. The comparator IC3 compares the levels of the output signals STa and STb and outputs a logic signal that is at the H level when STa> STb and at the L level when STa <STb, as shown in FIG. As the origin signal SZn. In the present embodiment, a time point at which the origin signal SZn transits from the H level to the L level is referred to as an origin time point (origin point) Tog and a generation timing of the origin point signal SZn means an origin time point Tog . The origin position (origin time point Tog) here is a point at which the optical axis AXf of the f? Lens system FT passes, as the reference point, (Or a predetermined time before) the start timing of pattern drawing along the drawing line SLn, rather than referring to the origin as an absolute position which is always set to fall by a certain distance in the main scanning direction of the drawing line SLn will be.

The origin time Tog becomes a moment at which the levels of the output signals STa and STb coincide with each other while the level of the output signal STa rises while the level of the output signal STb rises. STa and STb of the spot light SPr are determined based on the relationship between the width dimension of the light receiving surfaces PD1 and PD2 and the size of the spot light SPr and the relationship between the scanning speed Vh of the spot light SPr and the light- When the diameter of the spot light SPr is larger than the width dimension of the dead band and smaller than the width dimension of the light receiving surface PD1, the output signals STa and STb Becomes a waveform due to the level change as shown in Fig. 5A, and a stable origin signal SZn can be obtained.

Fig. 6 is a diagram showing an example in which the selection optical element OSn (OS1 to OS6) for selectively distributing the beam LB from the light source device LS to one of the six drawing units U1 to U6 And shows a schematic configuration of the beam switching unit. The reference numerals of the respective members in Fig. 6 are the same as those shown in Fig. 1, but the reflection mirrors M1 to M12 shown in Fig. 1 are appropriately omitted. The light source device LS constituted by the fiber amplifier laser light source is connected to the drawing control device 200 to exchange various kinds of control information SJ. The light source apparatus LS has a clock circuit for generating a clock signal CLK of an oscillation frequency Fa (for example, 400 MHz) when the beam LB is pulsed in the inside, In response to the clock signal CLK, on the basis of the rendering data SDn (bitmap data having one pixel as one bit) for each of the rendering units Un, The light emission of a few minutes and the repetition of the emission stop of a predetermined number of clock pulses).

The drawing control device 200 receives the origin signals SZn (SZ1 to SZ6) output from the origin sensors (photoelectric conversion elements DTo) of the drawing units U1 to U6 and outputs them to the drawing units U1 to U6 A polygon rotation control section for controlling the rotation motor RM of the polygon mirror PM so that the rotation speed and the rotation angle phase of each of the polygon mirrors PM are in a specified state; ) Based on the origin signals SZn (SZ1 to SZ6) of the drive signals DF1 to DF6 as ultrasound signals to be supplied to each of the plurality of drive signals DF1 to DF6. 6, the optical element OS4 for selection is selected from among the six optical elements OS1 to OS6 and the beam LB from the light source unit LS (the pattern of the pattern drawn by the imaging unit U4) The intensity of which is modulated by the imaging data) toward the incident mirror IM4 and supplies it to the imaging unit U4 as the beam LB4. If the selection optical elements OS1 to OS6 are provided in series with the optical path of the beam LB as described above, the selection from the light source device LS can be performed by the transmittance and the diffraction efficiency of each of the selection optical elements OSn. The intensity (peak intensity of the pulse light) of the selected beams LB1 to LB6 is different depending on the order of the optical elements OSn. For this reason, the drawing control device 200 is controlled so that the relative intensity difference of the beams LB1 to LB6 incident on each of the drawing units U1 to U6 is within a predetermined allowable range (for example, within ± 5% (Amplitude or power of the high-frequency signal) of each of the driving signals DF1 to DF6.

Fig. 7 is a diagram showing a specific configuration around the optical elements OSn (OS1 to OS6) and the incident mirrors IMn (IM1 to IM6). The beam LB emitted from the light source LS is incident on the selection optical element OSn as a parallel beam of a minute diameter (first diameter) of, for example, 1 mm or less in diameter. The incident beam LB is not diffracted by the selection optical element OSn but transmitted as it is during the period in which the drive signal DFn as the high frequency signal (ultrasonic signal) is not inputted (the drive signal DFn is off) do. The transmitted beam LB passes through the condenser lens Ga and the collimator lens Gb provided along the optical axis AXb on the optical path and enters the optical element OSn on the subsequent stage. At this time, the beam LB passing through the condensing lens Ga and the collimator lens Gb through the selection optical element OSn is coaxial with the optical axis AXb. The condensing lens Ga is a condensing lens that converts the beam LB (parallel light flux) transmitted through the selection optical element OSn to the position Ps of the surface Ps positioned between the condensing lens Ga and the collimator lens Gb To be a beam waist. The collimator lens Gb uses the beam LB diverging from the position of the surface Ps as a parallel beam. The diameter of the beam LB, which is collimated by the collimator lens Gb, becomes the first diameter. The rear focal position of the condensing lens Ga and the front focal position of the collimator lens Gb coincide with the plane Ps within a predetermined allowable range, Are arranged to coincide with the diffraction points in the element OSn within a predetermined allowable range.

On the other hand, during a period in which the drive signal DFn as a high-frequency signal is being applied to the selection optical element OSn, the incident beam LB passes through the beam LBn diffracted by the selection optical element OSn Diffracted light) and a zero-order beam LBnz that has not been diffracted. The intensity of the diffracted beam LBn is about 80% at the maximum when the intensity of the incident beam LB is 100% and the decrease due to the transmittance of the selection optical element OSn is ignored, Is the intensity of the zero-order beam LBnz. The zero order beam LBnz passes through the condenser lens Ga and the collimator lens Gb and is transmitted through the rear selection optical element OSn to be absorbed by the absorber TR. The beam LBn (parallel light flux) deflected in the -Z direction by the diffraction angle corresponding to the frequency of the high frequency of the drive signal DFn passes through the condenser lens Ga and is incident on the incident mirror IMn provided on the surface Ps, . The beam LBn directed from the condenser lens Ga to the incident mirror IMn passes through the optical axis AXb from the optical axis AXb because the front focal position of the condensing lens Ga is optically conjugate with the diffraction point in the selection optical element OSn. And the eccentric position proceeds parallel to the optical axis AXb and converges (converges) to be a beam waist at the position of the surface Ps. The position of the beam waist is set so as to be optically conjugate with the spot light SP projected onto the substrate P via the drawing unit Un.

The beam LBn diffracted by the selection optical element OSn is reflected by the incident mirror IMn in the -Z direction from the incident mirror IMn by arranging the reflecting surface of the incident mirror IMn or the vicinity thereof at the position of the surface Ps And is incident on the imaging unit Un along the optical axis AX1 (see Fig. 2) via the collimator lens Gc. The collimator lens Gc converts the beam LBn converged / diverged by the condenser lens Ga into a parallel light beam coaxial with the optical axis AX1 of the collimator lens Gc. The diameter of the beam LBn made parallel to the collimator lens Gc becomes substantially equal to the first diameter. The rear focal point of the condensing lens Ga and the front focal point of the collimator lens Gc are disposed at or near the reflecting surface of the entrance mirror IMn within a predetermined allowable range.

As described above, the front focal position of the condensing lens Ga and the diffraction point in the selection optical element OSn are optically conjugated with each other, and the incident mirror IMn The optical axis AXb of the light-converging point on the surface Ps of the beam LBn can be changed by changing the frequency of the drive signal DFn of the optical element OSn for selection by +/-? The amount of eccentricity (shift amount) can be changed. As a result, the spot light SP of the beam LBn projected onto the substrate P from the imaging unit Un can be shifted by ± ΔSFp in the sub-scanning direction. The shift amount |SFp | is calculated based on the maximum range of the deflection angle of the optical element OSn itself, the size of the reflecting surface of the incident mirror IMn, the magnitude of the reflecting surface of the optical system (Relay system), the limit of the reflection plane RP of the polygon mirror PM in the Z direction, the magnification from the polygon mirror PM to the substrate P (magnification of the f? Lens system FT) But can be adjusted in the range of about the effective size (diameter) of the spot light SP on the substrate P or about the pixel size Pxy defined on the painting data. This makes it possible to prevent overlapping errors between a new pattern to be drawn on the substrate P and a pattern already formed on the substrate P by each of the drawing units Un, It is possible to correct the joint error between the new patterns to be imaged on the wafer with high accuracy and high speed.

Next, with reference to Figs. 8 and 9, reproducibility of the generation timing of the origin signal SZn from the origin sensor (the beam transmission system 60a and the beam reception system 60b) configured as shown in Figs. 3 and 4 Deviation error) will be described. This measurement or calculation can be performed using a processor (CPU) or the like in the imaging control device 200 shown in Fig. 6, and the origin signal SZn may be sent to an external waveform measurement device or the like. 8 is a plan view of the eight-sided polygon mirror PM shown in Fig. 3 or Fig. 4. Here, with respect to each of the eight reflective surfaces RP, the origin signal (Fig. RPc, RPd, RPe, RPf, RPg, and RPh in the direction opposite to the rotation direction (clockwise rotation) of the polygon mirror PM to obtain the reproducibility of the polygonal mirror PM. A rotation reference mark Mcc for detecting the origin of rotation of the polygon mirror PM is formed on the upper surface (or lower surface) of the polygon mirror PM. The rotation reference mark Mcc is detected by a reflection type photoelectric sensor (also referred to as a &quot; circumference detection sensor &quot;) that outputs a pulse shape detection signal every time the polygon mirror PM makes one revolution. When the reproducibility of the origin signal SZn is measured, it is necessary to specify the reflection surface of the polygon mirror PM detected by the origin sensor. Therefore, the detection signal (rotation reference mark Mcc) , The reflective surfaces RPa to RPh of the polygon mirror PM are specified.

Further, when measuring the reproducibility of the timing of generation of the origin signal SZn, it is necessary to consider the influence of the speed fluctuation (speed imbalance) of the polygon mirror PM. The velocity fluctuation of the polygon mirror PM can be measured by the above-described main-current detecting sensor, but in this embodiment, the velocity fluctuation of the polygon mirror PM is measured based on the origin signal SZn. Assuming that the polygon mirror PM is rotated at 36,000 rpm and the polygon mirror PM in the drawing controller 200 is servo-controlled as described above, the polygon mirror PM rotates at 600 revolutions per second, The cycle time TD for one rotation becomes 1/600 second (approximately 1666.667 mu S). The actual time period TD from the origin time Tog of the arbitrary one of the origin signals SZn to the origin time Tog of the ninth pulse is set so that the light source LS emits pulses (For example, two times or more) higher than the oscillation frequency Fa used. Since the polygon mirror PM rotates at a high speed with inertia, there is a low possibility that velocity unevenness occurs during one rotation. However, depending on the characteristics of the servo control, there is a slight variation in the design time period TD in the period of several mS to several tens of mS .

9 is a view for explaining a method of measuring the reproducibility (deviation) of the generation timing of the origin signal SZn. Here, for simplicity of description, a method of obtaining the reproducibility of the origin time Tog2 of the origin signal SZn generated corresponding to the reflecting surface RPa of the polygon mirror PM shown in Fig. 8 is exemplified, The same can be applied to each of the other reflection surfaces RPb to RPh. The origin time Tog1 occurring at the immediately preceding timing of the origin time Tog2 is obtained as the origin signal SZn generated corresponding to the reflection surface RPh of the polygon mirror PM in the case of Fig. Thus, in a state in which the polygon mirror PM is rotated at the prescribed speed, the time from the origin time Tog1 corresponding to the reflection surface RPh to the origin time Tog2 corresponding to the next reflection surface RPa (For example, 10 times or more) for each rotation of the polygon mirror PM is repeatedly measured at the time point of the origin interval time? Tmn (n = 1, 2, 3, ...). 9, for the sake of simplicity, the waveforms of the origin signals SZn (a) 1 to SZn (a) 7 generated while the polygon mirror PM is being rotated seven times are shown as waveforms obtained in correspondence with the reflection surface RPh And the origin time (Tog1) is aligned on the time axis.

Assuming that the fluctuation of the rotation speed of the polygon mirror PM is zero, there is a deviation in the measured values of each of the reference point interval times? Tmn to be constant. Since this deviation becomes the deviation width DELTA Te of the generation timing of the origin time Tog2 corresponding to the reflection surface RPa, the reproducibility of the origin signal SZn is the same as that of the plurality of origin time Tog2 distributed within the deviation width DELTA Te A standard deviation value?, Or a 3? Value that is three times the standard deviation value?. As described above, when the light source LS pulses the beam LB at the cycle Tf, the 3? Value as the reproducibility is preferably smaller than the cycle Tf. In the above description, the variation of the rotation speed of the polygon mirror PM (velocity unevenness) is assumed to be zero. However, the waveform of the origin signal SZn is analyzed by using a waveform measuring device that samples the signal waveform with a resolution of nanoseconds or less, When the round trip time (one round trip time) of the polygon mirror PM is measured, it has been found that the round trip time fluctuates by +/- several nS depending on the round trip. Therefore, the reference time interval? Tmn (n = 1, 2, 3,..., Main number of times) measured as shown in Fig. 9 is corrected by the error caused by the velocity fluctuation of the polygon mirror PM in the measurement period of the reference point interval time? It is necessary to correct it in minutes.

10 is a diagram schematically showing a method of predicting a time error due to the speed fluctuation of the polygon mirror PM. In the present embodiment, the origin interval time DELTA Tmn corresponding to each of the eight reflective surfaces RPa to RPh is measured for each of a plurality of rounds of the polygon mirror PM. 10, the initial position (initial origin time Tog) during one rotation of the polygon mirror PM is set to the reflection surface RPa, and the polygon mirror PM is generated from the reflection surface RPa during two rotations The waveform of the origin signal SZn is shown schematically. Here, the origin time interval time from the origin time Tog corresponding to the reflection surface RPa of the origin signal SZn to the origin time Tog corresponding to the neighboring reflection surface RPb is defined as DELTA Tma Similarly, hereinafter, the time interval of the origin point from the adjacent reflection surface RPb to the reflection surface RPc is denoted by? Tmb, ... The time interval of the origin point from the adjacent reflecting surface RPh to the reflecting surface RPa is defined as DELTA Tmh. In the first round of the polygon mirror PM, the origin points Tog, which are generated in correspondence with the eight reflective surfaces RPa to RPh, respectively, are set as the start point, and the reflection surface of the polygon mirror PM RPa, RPa, RPa) TDh is measured. Each of the main times TDa to TDh may be obtained by a total value of eight origin interval times DELTA Tma to DELTA Tmh corresponding to each of the eight reflective surfaces RPa to RPh. Each of the main times TDa to TDh (or the origin interval time DELTA Tma to DELTA Tmh) is repeatedly measured while the polygon mirror PM is rotated N times, for example. This makes it possible to acquire the data of each of the main times TDa to TDh, which are displayed from the origin time Tog according to each of the eight reflective surfaces RPa to RPh, over N rotations.

Next, the average cycle time ave (TDa) to ave (TDh) of the cycle times TDa to TDh acquired over the N weeks are calculated. For example, the main clock time TDa is divided into TDa (1), TDa (2), TDa (3), ..., TDa TDa (1) + TDa (2) + TDa (3) +, TDa (N) + TDa (N)] / N.

Next, it is assumed that each of the home position interval times? Tma to? Tmh measured on the second and subsequent occasions shown in FIG. 10 includes an error due to the influence of velocity fluctuation in the main circuit of the immediately preceding polygon mirror PM For example, it is assumed that the home position interval time ΔTma measured after the second week has fluctuated by the ratio of the main time interval TDa measured in the preceding main routine to the average main time ave (TDa), and the expected interval of the home position interval time ΔTma The time? Tma 'is calculated. At this time, an average interval time ave (? Tma) of the N-1 home position interval times? Tma measured at each of the main positions after the second week is obtained. Then, the ratio of the average main time ave (TDa) and the measured main time TDa is multiplied by the average interval time ave (DELTA Tma) to calculate the expected interval time DELTA Tma 'in which the speed variation is corrected. Thereby, the difference value between the actually measured home position interval time? Tma and the expected interval time? Tma 'is obtained as a more accurate deviation value? Of the home position time Tog corresponding to the reflection surface RPa. The deviation amount of the origin time point Tog of the origin signal SZn corresponding to each of the other reflection surfaces RPb to RPh is also obtained by the similar calculation. As described above, it is only necessary to repeatedly measure the origin interval times DELTA Tma to DELTA Tmh, which are the generation intervals of the origin time Tog of the origin signal SZn, during the rotation of the polygon mirror PM plural times, Accurate reproducibility (such as 3? Value) can be obtained by reducing the error caused by the speed fluctuation.

[Example of measurement]

The focal length Fgs of the lens system GLb in the beam receiving system 60a of the origin sensor is made to be equal to the focal length f0 of the f? Lens system FT (for example, 100 mm) The photoelectric conversion element DTo is arranged at the position of Fgs and the polygon mirror PM is rotated at about 38000 rpm to generate the reflection surfaces RPa to RPh of the polygon mirror PM The reproducibility of the origin point signal SZn (origin time point Tog2) was measured, but the results shown in Fig. 11 were obtained. In FIG. 11, the horizontal axis represents angular positions (RPa? RPb, RPb? RPc, ... RPh? RPa) between the measured reflection surfaces, and the vertical axis represents the interval time? Tma To? Tmh (μS). The interval times DELTA Tma to DELTA Tmh are obtained by dividing the waveform data of the origin signal SZn continuously generated over 10 rotations of the polygon mirror PM into a digital waveform having a sampling rate of 2.5 GHz (0.4 nS) And stored in a storage device, and the waveform data thereof was analyzed and actually measured.

As shown in Fig. 11, the interval times? Tma to? Tmh after the variation of the main speed is corrected have a deviation between 197.380 μS and 197.355 μS. When the rotation speed of the polygon mirror PM is precisely rotated at 38000 rpm, the calculation interval times? Tma to? Tmh are each 197.368 μS. The deviation of the interval time DELTA Tma to DELTA Tmh can be obtained, for example, when each of eight positive angles (vertex angle, apex angle) formed by mutually adjacent reflection surfaces among the respective reflection surfaces RPa to RPh of the polygon mirror PM is precisely 135 degrees or the distance from the rotation axis AXp to each of the reflection surfaces RPa to RPh is not precisely fixed. The deviation of the interval time DELTA Tma to DELTA Tmh may also be caused by the degree of eccentricity error of the polygon mirror PM with respect to the rotation axis AXp. In Fig. 11, the deviation of each of the interval times DELTA Tma to DELTA Tmh is calculated The 3σ value was 2.3 nS to 5.9 nS. This means that when the pulse oscillation frequency of the beam LB from the light source LS is 400 MHz (period 2.5 nS), an error of about 3 pulses or more is generated with respect to the scanning position of the spot light. The diameter φ of the spot light SP is 4 μm, the pixel size Pxy is 4 μm square on the substrate P, and one pixel is drawn as two pulses of the spot light SP , It means that the position of the pattern to be drawn along the drawing line SLn has a deviation of about 5 占 퐉 (exactly 4.8 占 퐉) in the main scanning direction if the 3? Value is about 6 nS.

corresponding to the pulse interval distance DELTA Yp, when the focal distance of the f? lens system FT is fo and the distance (1/2 of the spot diameter) of the pulse interval of the spot light SP on the substrate P is DELTA Yp, The angle change ?? p of the projection optical system PM (reflecting surface) becomes ?? p ?? APPp / fo. On the other hand, assuming that the moving distance of the laser beam Bgb (spot light SPr) on the photoelectric conversion element DTo corresponding to the angle change ?? p is? Yg, the lens system (light receiving element) From the focal length Fgs of the lens group GLb, the movement distance? Yg becomes? Yg? ?? p 占 Fgs. Since the generation accuracy of the origin time Tog of the origin signal SZn is preferably matched to the accuracy (resolution) of 1/2 or less of the pulse interval distance? Yp of the spot light SP, The scanning speed of the laser beam Bgb (spot light SPr) on the substrate P is made twice as fast as the scanning speed of the spot light SP on the substrate P. That is, the relation of? Yg? 2? Yp is preferable. For this reason, in the present embodiment, it is needless to say that the focal length Fgs of the lens system GLb is set to about twice the focal length fo of the f? Lens system FT, but may be twice or more.

12 shows a case in which the focal length Fgs of the lens system GLb is changed to Fgs≈2 x fo by using another imaging unit having the same configuration as that of the imaging unit Un actually measured in Fig. 11, . The vertical axis and the horizontal axis in Fig. 12 are the same as those in Fig. 11, but the scale in the vertical axis in Fig. 12 has a scale of 2 nS (5 nS in Fig. 11). The scanning speed on the photoelectric conversion element DTo of the spot light SPr is set to about twice the scanning speed of the spot light SP on the substrate P so that the distribution of the deviation times ΔTma to ΔTmh The calculated 3 sigma value becomes 1.3 nS to 2.5 nS, which is improved to almost half as compared with the case of Fig. Therefore, in this case, if the diameter φ of the spot light SP is 4 μm, the pixel size Pxy is 4 μm square on the substrate P, and one pixel is drawn for two pulses of the spot light SP, The deviation of the position in the main scanning direction of the pattern drawn along the drawing line SLn is halved to about 2.5 占 퐉.

As described above, the origin sensor beam Bga projected on the reflection surfaces RPa to RPh of the polygon mirror PM is projected onto the reflecting surface RPa to RPh with a predetermined thickness (for example, 1 to 2 mm in diameter), it is possible to reduce the influence of roughness (such as polishing marks) on the surface of each of the reflective surfaces RPa to RPh and to accurately detect an average surface angle change have. On the other hand, the diameter dimension of the spot beam SPr of the reflected beam Bgb focused on the photoelectric conversion element DTo is determined by the width dimension of the light receiving surfaces PD1 and PD2 in the beam scanning direction, Receiving surface PD2 of the light-receiving surface PD2. The diameter of the spot light SPr in the scanning direction is set to be smaller than the width dimension of the small one of the light receiving surfaces PD1 and PD2 so as to obtain the signal waveform as shown in [A] in Fig. 5, Respectively. Therefore, the focal length Fgs of the lens system GLb incident on the reflected beam Bgb is set to be longer than the focal length fo of the f? Lens system FT to satisfy such a condition.

In addition, since the intensity distribution in the cross section of the beam Bga emitted from the semiconductor laser light source LDo shown in FIG. 4 is an ellipse having an aspect ratio of about 1: 2, (Main scanning direction) of each of the reflection surfaces RPa to RPh and the minor axis direction of the ellipse is aligned with the rotation axis AXp of the polygon mirror PM. This makes it possible to effectively reflect the beam Bga as the reflected beam Bgb even if the height of each of the reflecting surfaces RPa to RPh of the polygon mirror PM (the dimension in the direction of the rotation axis AXp) is small The numerical aperture NA in the scanning direction of the reflected beam Bgb leading to the photoelectric conversion element DTo can be made larger than the numerical aperture NA in the non-scanning direction, (In the direction transverse to the light-receiving surfaces PD1 and PD2 in Fig. 5) can be increased, and the contrast can be sharpened.

Instead of the type of generating the origin signal SZn by comparing the magnitudes of the output signals STa and STb from the two light receiving surfaces PD1 and PD2 as the photoelectric conversion elements DTo as shown in Fig. 5, A type that generates the origin signal SZn by comparing the signal level from the slit-shaped light receiving surface with the reference voltage may be used. In the case of this type, the reproducibility of the origin time Tog of the origin signal SZn is likely to become better as the slope of the rising portion or the descending portion of the signal waveform becomes steep (the shorter the response time is) The scanning speed of the spot light SPr traversing the light receiving surface of the light spot is made higher than the scanning speed of the spot light SP for painting and the spot light SPr is condensed by the lens system GLb as small as possible, It is preferable to increase the strength of the film.

The origin detection sensor (the lens system GLb and the photoelectric conversion element DTo) according to the present embodiment shown in Fig. 3 is configured to detect the origin detection beam Bga And photoelectrically detects the reflected beam Bgb from the polygon mirror PM. 3, immediately after the reflective surface RPa of the polygon mirror PM reaches the angular position of RPa ', the imaging beam LBn is not incident on the f? Lens system FT (in the blank state ), But the lens system GLb has a period of incidence. The drawing beam LBn is controlled so as not to be incident on the drawing unit Un by the pulse oscillation of the beam LB from the light source unit LS or the control of the optical element OSn for selection during the blank period do. Thus, even in the blank period, the selection optical element OSn is turned on only for a period in which the imaging beam LBn can enter the lens system GLb, and the beam LB is emitted from the light source apparatus LS at the oscillation frequency Fa And the reflected beam of the beam LBn reflected by the polygon mirror PM by the photoelectric conversion element DTo may be received. In such a configuration, the imaging beam LBn incident on the lens system GLb during the blank period can be used as the origin detection beam.

However, the tendency of the deviation of the interval times? Tma to? Tmh shown in FIG. 12 and the tendency of the deviation of the interval times? Tma to? Tmh shown in FIG. 11 are largely different from the nanosecond order, It is considered that the tendency of the angular error of each angle angle between the polygon mirrors PM used in the actual measurement of the workpiece is considered to be due to the difference between the individual differences (machining tolerances) and eccentric errors at the time of rotation. The tendency and degree of the machining tolerance and the eccentricity error of the polygon mirror PM may be different for each of the rendering units Un (U1 to U6) as in the actual measurement example of Fig. 11 or 12, The deviation error also differs for each of the rendering units Un (U1 to U6). Therefore, in the present embodiment, in order to reduce the influence of the deviation error of the interval time? Tma to? Tmh caused by the processing tolerance of the polygon mirror PM, the eccentricity error, or the shape deformation of the polygon mirror PM due to the temperature change, The delay time TD set from the origin time Tog of the origin signal SZn to the start of drawing operation is adjusted for each of the reflection surfaces RPa to RPh of the polygon mirror PM. In other words, the time interval? Tma to? Tmh of the origin time Tog of the origin signal SZn generated for each of the reflection surfaces RPa to RPh of the polygon mirror PM is set to be within a period of one turn of the polygon mirror PM And corrected by signal processing so that they become almost equal.

13 is a diagram showing a state in which a continuous pattern of five pixels in the main scanning direction is superimposed by superimposing the spot light SP for two pulses per pixel in the main scanning direction and the sub scanning direction at 1/2 of the spot size? Fig. 13, the drawing of a pattern for five pixels after a constant delay time TD starts with the origin time Tog of the origin signal SZn generated for each of the reflection surfaces RPa to RPh of the polygon mirror PM as a start point . The deviation of the generation timing (origin time Tog) of the origin signal SZn in FIG. 13 (deviation of interval time? Tma to? Tmh) is shown in the case of FIG. 12 as an example. As shown in Fig. 13, when the five-pixel pattern drawn by the spot light SP of the beam LBn scanned by the reflecting surface RPa of the polygon mirror PM is taken as a reference, The pattern of five pixels drawn by the spot light SP of the beam LBn scanned by each of the other reflection surfaces RPb to RPh has a deviation in the main scanning direction. Therefore, the edge extending in the sub-scanning direction of the pattern drawn becomes meandering in pixel units (one to two pixels). The number of meandering pixels depends on the deviation of the interval time? Tma to? Tmh, not by the line width of the pattern to be drawn (the number of pixels in the main scanning direction). Therefore, when the size of one pixel is 4 mu m square on the substrate P, if a pattern of 8 mu m (two pixels) as the minimum line width is continuously drawn in the sub-scanning direction, The pattern is observed as a meandering pattern with a large line width.

Fig. 14 is a graph schematically showing a characteristic graph according to the experimental example of Fig. 12, and RPa / b to RPh / a of the horizontal axis represents angular positions (RPa to RPb, RPb? RPc, ... RPh? RPa), and the vertical axis represents the same reference point interval time? Tma to? Tmh (占)) as in Fig. The reference time Tsr in Fig. 14 is a time required for rotating the polygon mirror PM by 45 degrees when the eight-sided polygon mirror PM is precisely rotated at a rotation speed of 38000 rpm, which is 197.368 mu s. The times Tab, Tbc, Tcd, Tde, Tef, Tfg, Tgh, and Tha in FIG. 14 are center time intervals of a 3σ value of three times the standard deviation shown in FIG. The average value obtained by dividing the total value of the interval times Tab, Tbc, Tcd, Tde, Tef, Tfg, Tgh and Tha by 8 is used as the actual reference time Tsr 'since the rotation speed of the polygon mirror PM at the actual measurement has an error. .

Thus, in the present embodiment, the origin interval time ΔTma to ΔTmh of the origin signal SZn outputted with the characteristic as shown in FIG. 14 is corrected by the delay circuit so as to be matched with the reference time Tsr '. 15 is a time chart explaining the generation state of the origin signal SZn 'obtained by correcting the origin signal SZn. 15, as an example, the origin time (Tog) generated corresponding to the reflection surface RPb of the polygon mirror PM from the origin signal SZn, (Tog), but the same is also true for the other reflection surfaces RPb to RPh. The origin time Tog corresponding to each of the reflection surfaces RPa and RPb of the origin signal SZn is set to the interval time Tha, Tab, Tbc ... Lt; / RTI &gt; Here, when the origin time (Tog) corresponding to the reflection surface (RPa) is taken as the starting point, an origin time ((Rz)) corresponding to the reflection surface (RPa) of the corrected origin signal SZn ' Tog ') is generated by adjusting the delay time? Taa so as to be the reference time Tsr' from the origin time (Tog ') corresponding to the immediately preceding reflection surface RPh. The origin time Tog 'corresponding to the reflection surface RPb of the corrected origin signal SZn' is set such that the reference time Tsr 'from the origin time Tog' corresponding to the previous reflection surface RPa And adjusted by the delay time? Tob. Likewise, the origin time Tog 'of the origin signal SZn' after correction corresponding to each of the other reflection surfaces RPc to RPh is also the origin signal SZn 'corresponding to each of the immediately preceding reflection surfaces RPb to RPg, ? Tod,? To,? Tof,? Toog and? Toh so as to be the reference time Tsr 'with respect to the origin time Tog' The delay times? Toa to? Toh for each of the reflection surfaces RPa to RPh are obtained from difference values between each of the interval times Tab to Tha and the reference time Tsr 'specified as shown in Fig.

16 is a circuit diagram of a correction circuit (correction section) for generating a corrected origin signal SZn '(correction origin signal SZn') by inputting the origin signal SZn from the photoelectric conversion element DTo, ). Fig. This correction circuit is provided as a part of the painting control device 200 shown in Fig. 16, the correction circuit includes a counter circuit 210 (Fig. 16) that counts a clock signal CCK set at a frequency (for example, 800 MHz) higher than the frequency Fa (400 MHz) of the clock signal CLK from the light source device LS A shift register 212 for setting a preset value corresponding to each of the interval times Tab to Tha in the counter circuit 210 and a shift register 212 for controlling the shift operation of the shift register 212 And has a shifter control circuit 214. In this embodiment, a sensor 220 for photoelectrically detecting the reflected light of the rotation reference mark Mcc shown in Fig. 8, and a logic level clock pulse signal (a polygon mirror PM (One pulse per one rotation of the motor) Sj). The shifter control circuit 214 generates a shift signal Sff (address designation signal) based on the reflection plane RPa of the polygon mirror PM as a start point based on the main clock signal Sj and the origin signal SZn And outputs it to the shift register 212. The shift register 212 has eight registers 212A corresponding to the eight reflective surfaces RPa to RPh and eight registers 212A are connected to be a ring shift register and are responsive to the shift signal Sff And sequentially shifts the preset values held in the respective registers to neighboring registers. The output from one of the eight registers 212A of the shift register 212 is applied to the counter circuit 210. [

The counter circuit 210 outputs a preset value (e.g.,? Toa) from the shift register 212 set in response to the reset signal RST to the origin signal SZn generated corresponding to the reflection plane RPa, In response to the pulse of the clock signal (CCK) from the origin time (Tog) of the origin point signal (Tog), and generates a pulse-like origin signal (SZn ') at a moment when the count value becomes zero. The counter circuit 210 receives the origin signal SZn 'as the reset signal RST and after a predetermined time (less than the reference time Tsr') from the origin time Tog 'of the origin signal SZn' (E.g.,? Tob) from the shift register 212 shifted by one in response to the set value Sff. With this operation, the corrected origin signal SZn 'output from the counter circuit 210 is substantially constant with the deviation of the interval time Tab to Tha for each reflection surface RPa to RPh of the polygon mirror PM corrected The origin time (Tog ') is inscribed in the reference time Tsr'.

The preset values stored in each of the eight registers 212A of the shift register 212 are stored in the memory unit in the drawing control device 200 and are read and preset there. Since the interval times Tab to Tha and the reference time Tsr 'shown in Fig. 14 are different depending on the rotation speed VR of the polygon mirror PM, the characteristics shown in Figs. 12 and 14 are measured beforehand for the other rotation speed VR, Determines a preset value corresponding to each of the delay times? Toa to? To according to the reference time Tsr 'for each speed VR and stores it as a table in the memory unit in the drawing control device 200. [ Therefore, when the rotation speed VR of the polygon mirror PM is changed from the standard value (for example, 38000 rpm) during the drawing operation, the delay times? Toa to? Toh (corresponding to the rotation speed VR of the polygon mirror PM after the change) Is read from the table in the memory unit in the drawing control device 200 and set in the register 212A of the shift register 212. [ The relationship of the preset values in accordance with the delay times? Toa to? Toh stored in the table in the drawing controller 200 can be obtained, for example, by setting the rotation speed VR of the polygon mirror PM at 40000 rpm, 38000 rpm, 36000 rpm, And the preset values of the delay times DELTA Toa to DELTA Toh corresponding to the rotational speed VR therebetween may be obtained by linear interpolation.

According to the embodiment described above, by using the correction origin signal SZn 'for controlling the start of imaging, the reproducibility of the imaging start point is improved, and the origin time point for each of the reflection surfaces RPa to RPh of the polygon mirror PM Deviation of the absolute position of the substrate P in the main scanning direction on the substrate P at the start of drawing is also reduced and the quality of the pattern to be drawn is improved.

[Modified Example 1]

As shown in Fig. 1, if the plurality of drawing units Un are provided adjacent to each other, the temperature in each drawing unit Un tends to rise. The temperature rise can be suppressed by the air conditioning or temperature control of the drawing unit Un. However, in order to reduce the noise (wind noise) generated when the polygon mirror PM is rotated at a high speed, The case may be provided or the cover may be provided around the polygon mirror PM, so that the air conditioning or the temperature control may not be effective. That is, it becomes difficult to well suppress the variation of the air temperature around the periphery of the polygon mirror PM or around the origin sensor (the beam transmitting portion 60a and the beam receiving portion 60b). When the base material of the polygon mirror (PM) is made of aluminum for weight reduction, the state of the reflection surface of the polygon mirror (PM) may be deformed to the order of sub-microns depending on the degree of such temperature change. The lens system GLa of the beam transmitting unit (beam transmitting system) 60a for generating the origin detecting beam Bga is made of plastic (resin mold) in order to unitize with the semiconductor laser light source LDo The beam Bga which is directed to the polygon mirror PM due to the change of the ambient temperature is liable to fluctuate from the parallel state to the convergent or divergent beam. Therefore, the focus state of the spot beam SPr of the reflected beam Bgb focused on the photoelectric conversion element DTo changes and the reproducibility of the origin signal SZn decreases or the beam Bga).

In this modified example, a temperature sensor for precisely measuring the temperature around the polygon mirror PM or around the origin sensor (the beam transmitting portion 60a and the beam receiving portion 60b) is provided, (3σ value) and the origin interval time ΔTma to ΔTmh (or the interval time Tab to Tha in FIG. 14) in advance in the shift register 212 of FIG. 16 The preset values corresponding to the delay times? Toa to? Toh are corrected according to the temperature measured by the temperature sensor. This reduces the deviation of the starting point of the rendering pattern from the main scanning direction due to the temperature change of the drawing unit Un.

[Modified example 2]

17 is a view showing the configuration of the origin sensor according to the second modified example. The polygon mirror PM in the drawing unit Un, the optical axis AXf of the f? Lens system FT, The arrangement of the light portion 60a and the beam light receiving portion 60b is shown in the XY plane. 17, the painting beam LBn is projected toward one reflecting surface RPa of the reflecting surface RP of the polygon mirror PM and one of the reflecting surfaces RPa of the polygon mirror PM A laser beam (origin detecting beam) Bga from the beam transmitting portion 60a is projected onto the reflecting surface RPb of the neighboring (immediately before) one. The angular position of the reflecting surface RPa in Fig. 17 indicates a state just before the spot light SP of the drawing beam LBn is positioned at the drawing start point of the drawing line SLn. Here, the reflecting surface RP (RPa) of the polygon mirror PM is arranged so as to be located at the entrance pupil plane orthogonal to the optical axis AXf of the f? Lens system FT. Strictly speaking, at the angular position of the reflective surface RP (RPa) at the moment when the principal ray of the beam LBn incident on the f? Lens system FT is coaxial with the optical axis AXf, The reflecting surface RP (RPa) is set at a position where the principal ray of the beam LBn directed to the mirror PM crosses the optical axis AXf. The distance from the main surface of the f? Lens system FT to the surface of the substrate P (light-converging point of the spot light SP) is the focal distance fo.

The beam Bga from the beam transmitting portion 60a is incident on the photosensitive functional layer of the substrate P by a lens system GLa similar to that of Fig. 4, as a parallel light flux of a non-photosensitive wavelength range, And is projected on the reflective surface RPb of the projection optical system. The reflected beam Bgb of the laser beam Bga reflected from the reflecting surface RPb is directed to a reflecting mirror (reflecting optical member) MRa having a reflecting surface perpendicular to the XY plane. The reflected beam Bgc of the beam Bgb reflected by the reflecting mirror MRa is projected toward the reflecting surface RPb of the polygon mirror PM again. The reflected beam Bgd of the beam Bgc reflected by the reflecting surface RPb is received by the beam receiving portion 60b. The beam light receiving section 60b is arranged so that the beams Bga and Bb are reflected at the moment when the reflecting surface RPb (and the other reflecting surfaces RP) of the polygon mirror PM become a specific angular position in the XY plane, Bgb, Bgc, Bgd) proceeds, and the beam receiving section 60b outputs the origin signal SZn in the form of a pulse. In FIG. 17, the beam Bga is shown as a simple line, but actually it is set to be a parallel beam having a predetermined width with respect to the rotational direction of the reflecting surface RP of the polygon mirror PM in the XY plane. Similarly, in FIG. 17, the beam Bgd is shown as a simple line, but actually it becomes a parallel beam having a predetermined width in the XY plane, and the beam Bgd is reflected by the beam receiving portion 60b As shown by the arrow Aw. The beam light receiving section 60b includes a photoelectric conversion element DTo for outputting the origin signal SZn when the beam Bgd is received and a beam spot Bgd on the photoelectric conversion element DTo And a lens system GLb that condenses as light SPr.

17, the beam reflected from the reflecting surface RP (RPb) of the polygon mirror PM is reflected twice by using the reflecting mirror MRa, Bgd are received by the photoelectric conversion element DTo. The scanning speed Vh of the spot light SPr on the light receiving surfaces PD1 and PD2 is obtained by reflecting the origin detecting beam Bga once at the reflecting surface RP (RPb) of the polygon mirror PM It can be doubled or more as compared with the case of Fig. 4 in which light is received by the photoelectric conversion element DTo. As a result, compared with the scanning speed Vsp on the substrate P of the drawing beam LBn (spot light SP), the origin detection beam Bgd (spot light SPr) on the photoelectric conversion element DTo The scanning speed Vh of the origin signal Szn can be doubled, and the reproducibility of the origin signal SZn can be improved as in the first embodiment. However, in the second modified example, it is not necessary to set the focal length Fgs of the lens system GLb provided in the beam receiving portion 60b to be twice or more the focal length fo of the f? Lens system FT, The scanning speed Vh of the light SPr can be doubled from the scanning speed Vsp of the spot light SP.

In the second modification, the origin detection beam Bga is projected on the reflection surface RPb immediately preceding the reflection surface RPa of the polygon mirror PM on which the imaging beam LBn is projected have. Therefore, in the case of the origin sensor as shown in Fig. 17, in a moment set at the angle of the reflecting surface RPa such that the spot light SP of the drawing beam LBn is positioned just before the drawing start point of the drawing line SLn , The origin signal SZn from the beam receiving portion 60b in Fig. 17 is set to be the origin time Tog. As described above, even when the polygon mirror PM is configured to reflect the imaging beam LBn and the origin detection beam Bga from different reflection surfaces, the corrected origin signal SZn 'is generated It is possible to reduce the deviation of the starting point of the rendering pattern from the main scanning direction.

[Second Embodiment]

In the second embodiment, the reference pattern formed on the outer peripheral surface of the rotary drum DR shown in Fig. 1 is scanned with the spot light SP of the beam LBn projected from the imaging unit Un, The reproducibility of the origin signal SZn or the origin interval time ΔTma to ΔTmh (or the interval time Tab to Tha in FIG. 14) is checked based on the photoelectric signal detected by the photodetector DTc shown in FIG. 2 , And the delay times Toa to Toh are set. A configuration in which a reference pattern is provided on the outer circumferential surface of the rotary drum DR and the positive reflected light generated when the reference pattern is scanned with the spot light SP is detected by the photodetector DTc in the imaging unit Un, For example, in International Publication No. 2015/152217 pamphlet.

18 is a graph showing the relationship between the photoelectric signals Sv generated from the photodetector DTc when the reference patterns PTL1 and PTL2 in the form of lines and spaces formed on the outer circumferential surface of the rotary drum DR are scanned with the spotlight SP Fig. The reference pattern PTL1 is a line pattern in which the line width of the spot light SP in the main scanning direction is 20 占 퐉 and extends in the sub scanning direction and the reference pattern PTL2 has a line width in the main scanning direction 20 占 퐉 and is a linear pattern of high reflectance extending in the sub-scanning direction. When the reference patterns PTL1 and PTL2 are scanned with the spotlight SP, the intensity of the regularly reflected light generated from the reference pattern PTL1 is low and the intensity of the regularly reflected light generated from the reference pattern PTL2 is high. Since the f? Lens system FT is telecentric, the regularly reflected light from the reference patterns PTL1 and PTL2 travels back to the optical path of the imaging beam LBn in Fig. 2 and reaches the polarization beam splitter BS1 do. Although not shown in Fig. 2, a condenser lens for converging the regularly reflected light (parallel beam equivalent to the beam LBn) transmitted through the polarizing beam splitter BS1 onto the photodetector DTc is provided. Thereby, the outer peripheral surface of the substrate P or rotary drum DR becomes conjugate with the light receiving surface of the photodetector DTc, and the light receiving surface of the photodetector DTc is projected onto the reference patterns PTL1 and PTL2 A conjugate image of the spot light SP is formed. Therefore, the signal Sv from the photodetector DTc becomes low level while the spotlight SP is projecting the reference pattern PTL1, and becomes high level while projecting the reference pattern PTL2 .

The waveform change of the signal Sv from the photodetector DTc is multiplied by the clock signal CLK or the clock signal CLK from the light source unit LS which makes the spot light SP pulse- ) Of the origin signal SZn is digitally converted into a sampling clock signal and stored and analyzed so that a spot based on the origin time Tog of the origin signal SZn (or the origin time Tog 'of the corrected origin signal SZn' The edge positions extending in the sub-scan direction of the reference patterns PTL1 and PTL2 can be measured based on the scan position of the light SP.

19 shows an example of a circuit configuration for digitally sampling the waveform of the signal Sv from the photodetector DTc and receives a signal Sv and outputs the level of the signal Sv in response to the sampling clock signal CLK2. A sampling clock signal (hereinafter, simply referred to as a clock signal) CLK2 (hereinafter simply referred to as a "clock signal") obtained by multiplying the frequency Fa of the clock signal CLK from the light source unit LS by two, A waveform storage section (memory section) 242 for storing the digitally converted data in the A / D conversion section 240 in response to the clock signal CLK2, a corrected origin signal An address generator 244 for generating a memory address value when data is stored in the waveform memory 242 based on the clock signal CLK2 and the clock signal CLK2, And a waveform analyzing unit 246 including a CPU for reading and analyzing the waveform data of the waveforms Sv and Sv. The information analyzed by the waveform analyzing unit 246 is sent to the drawing control apparatus 200 of FIG. 6 and the reproducibility (3 sigma value) of the origin signal SZn ', the confirmation of the interval time Tab to Tha, Used to modify Toh.

20 uses the circuit configuration of Fig. 19 to measure the deviation of the generation timing of the origin time Tog '(or the origin time Tog) of the origin signal SZn' (or the origin signal SZn) It is a time chart showing an example. In this embodiment, on the outer circumferential surface of the rotary drum DR, at the position in the sub-scanning direction (Y direction) corresponding to the vicinity of the scanning start point of the drawing line SLn of the drawing unit Un to be checked, Reference patterns PTL1 and PTL2 are formed. In the present embodiment, the rotation angle of the rotary drum DR is set and stopped such that the reference patterns PTL1 and PTL2 are positioned on the drawing line SLn.

20, the beam LB from the light source device LS shown in Fig. 6 immediately after the constant delay time? TD from the origin time Tog 'of the correction origin signal SZn' And drawing is started. Also, immediately before the pulse oscillation of the beam LB, the selection optical element OSn corresponding to the rendering unit Un to be the object also becomes on-state. A period during which the optical element for selection OSn is turned on and the beam LB is supplied to the object drawing unit Un as the beam LBn is determined by the fact that the spot light SP of the beam LBn is reflected by the reference pattern PTL1 , PTL2). During the ON state, the beam LB from the light source device LS continuously oscillates at the frequency Fa. When the spotlight SP scans the surface of the rotary drum DR immediately after the delay time? TD, the photoelectric signal Sv from the photodetector DTc changes in level to the waveform shown in Fig. The address generating unit 244 generates an address value that is incremented incrementally in response to the clock pulse of the clock signal CLK2 from the time Tu1 after the delay time? Tu from the origin time Tog ' Unit 242 sequentially stores a digital value (a value corresponding to the level of the signal Sv) from the A / D conversion unit 240 in the designated address value. Here, the delay time? Tu is set to? Tu>? TD and the time before the spot light SP reaches the reference patterns PTL1 and PTL2.

The address generating unit 244 and the waveform storing unit 242 perform the scanning operation for a period of time from the time Tu1 to the time Tu2, that is, a period in which the spot light SP scans the distance including the reference patterns PTL1 and PTL2, The waveform data of the signal Sv is stored in the waveform storing section 242 with the time resolution of the clock signal CLK2. The operation of the waveform memory described above is performed for the required number of times each time the beam LBn is scanned by the specified one reflection surface RP (for example, RPa) of the polygon mirror PM, A plurality of waveform data extending from the time Tu1 to the time Tu2 of the photoelectric signal Sv generated by the spot light SP scanned by the same reflective surface RP of the polygon mirror PM are stored in the memory 242. [ The waveform analyzing unit 246 analyzes the stored plurality of waveform data to check whether the reproducibility of the origin time (Tog ') of the origin signal SZn' is within a predetermined standard. For this purpose, the waveform analyzing unit 246 specifies a position (address position) in which the waveforms of the signal Sv rise or fall in accordance with the edge positions of the reference patterns PTL1 and PTL2, The midpoint position of the reference pattern PTL1 (low reflectance) is obtained, and the average position CTu (address position) of such intermediate position is obtained. Since the address value of one waveform data stored in the waveform storing section 242 corresponds to the clock pulse of the clock signal CLK2, the time from the time Tu1 to the average position CTu is equal to the period of the clock signal CLK2 By the product of the number of addresses from the time Tu1 to the average position CTu and the time? TPc from the origin time Tog 'of the origin signal SZn' to the average position CTu is calculated. The waveform analyzing unit 246 calculates a plurality of times? TPc by performing this analysis on each of the plurality of waveform data in which such analysis is stored. The waveform analyzing unit 246 obtains the 3σ value from the standard deviation value? Of the deviation of the calculated plurality of times? TPc, and sends the 3? Value to the drawing control device 200. [

Each of the time intervals Tab to Tha of the origin time Tog 'of the correction origin signal SZn' generated corresponding to each of the reflection surfaces RPa to RPh of the polygon mirror PM is corrected to the reference time Tsr ' A counter circuit for counting the clock signal CLK2 is added to the circuit configuration of Fig. 19, and a counter circuit for counting the clock signal CLK2 is added to the reflection origin signal SZn 'of the reflection surface of the polygon mirror PM And the origin time (Tog ') generated corresponding to the next reflection surface (RPb) of the reflection surface (RPa) are measured a plurality of times, and the average value And sends it to the drawing control device 200. Similarly, the interval time between different reflection surfaces is measured, and an average value of the obtained interval time is sent to the painting control device 200. [ The drawing control device 200 checks whether each of the interval times Tab to Tha sent is within the allowable range with respect to the reference time Tsr ' DeltaToa to DeltaToh to be set to the delay time.

According to the second embodiment as described above, it is possible to suppress the deviation of the imaging start position caused by the temporal variation of the corrected origin signal SZn '(or the origin signal SZn before correction), and the long- Pattern drawing can be performed. In this embodiment, the reproducibility and the interval time Tab to Tha of the origin signal SZn 'are checked using the reference patterns PTL1 and PTL2 formed on the outer peripheral surface of the rotary drum DR. The reference patterns PTL1 and PTL2 may be detected. In addition, a reference sheet (for example, a glass sheet, a stainless sheet, or the like having a thickness equal to that of the substrate P, which is flexible and has little deformation) having the reference patterns PTL1 and PTL2 formed thereon, May be wound around the rotary drum DR and fixed.

[Third embodiment]

21 is a diagram for explaining a method of test exposure for checking the accuracy of the correction origin signal SZn '(or the origin signal SZn before correction) according to the third embodiment. In this embodiment, A plurality of rectangular test patterns Tpt are arranged in a main scanning direction and a sub scanning direction in a matrix form and exposed on the substrate P on which the photosensitive layer is formed by one drawing unit Un. However, in the present embodiment, among the plurality of test patterns Tpt arranged in the sub-scan direction, the test pattern Tpt exposed in the column MPa is formed only by the reflection surface RPa of the polygon mirror PM The test pattern Tpt which is controlled to be imaged and exposed in the column MPb is controlled to be imaged only by the reflecting surface RPb of the polygon mirror PM. Likewise, the test pattern Tpt exposed in each of the columns MPc to MPh is controlled to be imaged by any one of the reflection surfaces RPc to RPh of the polygon mirror PM. That is to say, each of the test patterns Tpt is exposed by the spot light SP of the beam LBn reflected by only one reflection surface designated during one rotation of the polygon mirror PM, At a speed of 1/8 of the conveying speed of the conveying belt. Although it is not absolutely necessary to dispose a plurality of test patterns Tpt in the main scanning direction in the rows MPa to MPh, it is also possible to arrange the plurality of test patterns Tpt in the main scanning direction (Tpt) of the test pattern (Tpt).

The substrate P to be test exposed may be cleanly attached to the outer circumferential surface of the rotary drum DR with a sheet PEN film having a small expansion or contraction or an ultra thin glass sheet or stainless steel sheet. After the test-exposed substrate P is subjected to development processing or etching treatment, the state of formation of the edge portions Ef and Et extending in the sub-scan direction of the test pattern Tpt is magnified and observed by an inspection apparatus or the like. When the edge portions Ef and Et of the test pattern Tpt have deviations as shown in Fig. 13, for example, the edge portions Ef and Et of the test pattern Tpt corresponding to the reflection surface of the polygon mirror PM, The reproducibility of the origin time Tog 'of the correction origin signal SZn' is deteriorated.

21, the set of eight columns MPa to MPh of the test pattern Tpt drawn by each of the eight reflective surfaces RPa to RPh of the polygon mirror PM is repeated in the sub- . For example, the center position of the first test pattern (Tpt) in the first row (MPa) and the second row (MPa) in the sub-scan direction from the first row (MPa) Tpt) and the center position of the second test pattern (Tpt) at the same position with respect to the main scanning direction are specified and the test patterns (Tpt) arranged in the sub-scanning direction in accordance with the straight line (Lcc) And the positional error? Ytt in the main scanning direction between the center position between the edge portions Ef and Et and the straight line Lcc is measured. The position error? Ytt becomes substantially the same when each of the interval times Tab to Tha in the correction origin signal SZn 'is precisely adjusted to the reference time Tsr'. However, when there is a deviation in the measured position error? Ytt among the rows (MPb to MPh), it means that the correction to the reference time Tsr 'of the interval times Tab to Tha has deviated. That is, the interval times Tab to Tha in the origin signal SZn before the correction are changed. Since the variation of the interval time Tab to Tha can be estimated by analyzing the position error? Ytt, the drawing control device 200 corrects the delay times Toa to Toh and sets them in the shift register 212. [

As described above, according to the present embodiment, since the pattern (test pattern) exposed on the substrate P is inspected by only one reflection surface of the polygon mirror PM, the correction origin signal SZn '(or the origin It is possible to confirm the reproducibility of the origin time Tog '(or the origin time Tog) generated corresponding to each of the reflection surfaces RPa to RPh of the signal SZn. It is also possible to confirm a change in the deviation of the interval time Tab to Tha between the reflection surfaces RPa to RPh of the polygon mirror PM.

[Modifications of Third Embodiment]

21, it is necessary to rotate the rotary drum DR precisely at a predetermined speed (1/8 of the normal speed), but during the test exposure, the rotary drum DR is rotated about the center axis AXo in the main scanning direction. However, it is difficult to suppress the fluctuation of the position of the rotary drum DR in the main scanning direction to a micron order or a submicron order.

22, a linear reference pattern PTL3 continuous in the circumferential direction is provided at an end portion of the outer circumferential surface of the rotary drum DR in the direction in which the central axis AXo extends, do. The pattern detector DXa which is set on an extension line of the odd number of drawing lines SL1, SL3 and SL5 in the Y axis direction (main scanning direction) and has a detection area Axv for detecting the reference pattern PTL3 , A pattern detector DXb provided on an extension line of an even number of drawing lines SL2, SL4 and SL6 in the Y axis direction (main scanning direction) and having a detection area Axv for detecting the reference pattern PTL3 do. The pattern detectors DXa and DXb can frequently measure minute displacements in the Y-axis direction in the detection area Axv of the linear reference pattern PTL3 with a submicron order. When the reference pattern PTL3 is not provided on the outer circumferential surface of the rotary drum DR, the cross section of the rotary drum DR in the direction in which the central axis AXo extends is perpendicular to the central axis AXo The displacement of the reference plane in the Y-axis direction may be measured by a gap sensor (linear sensor) GSa or GSb which is a non-contact type of capacitance or optical. The measurement position of the gap sensor GSa is set equal to the orientation of the odd number of drawing lines SL1, SL3 and SL5 in the XZ plane orthogonal to the central axis AXo, The measurement position is set equal to the orientation of the even-numbered drawing lines SL2, SL4, and SL6 in the XZ plane.

The value of the positional displacement in the Y-axis direction of the rotary drum DR (substrate P) when each of the plurality of test patterns Tpt arranged in the sub-scan direction is exposed when the test exposure is performed as shown in Fig. Is measured by the pattern detectors DXa and DXb or the gap sensors GSa and GSb and stored in the drawing control device 200, for example. When the positional relationship of the test pattern Tpt exposed in a matrix form on the substrate P is measured by an inspection apparatus or the like, the position of the test pattern Tpt in the Y direction (main scanning direction) The measured value is corrected. This makes it possible to compensate for errors due to minute positional fluctuations in the Y-axis direction of the rotary drum DR (substrate P) generated during test exposure, and to prevent reflection surfaces RPa to RPh of the polygon mirror PM, The reproducibility of the correction origin signal SZn '(or the origin signal SZn before correction) generated corresponding to each of the reflection surfaces RPa to RPh of the polygon mirror PM can be checked with high accuracy. Changes in the deviation of the origin interval time Tab ~ Tha can also be checked with high accuracy.

[Fourth Embodiment]

Fig. 23 is a partial sectional view of the rotary drum DR according to the fourth embodiment. Fig. In this embodiment, a small opening 50J (also referred to as a concave portion) is provided in a part of the outer circumferential surface of the rotary drum DR, and a photoelectric conversion element DTo as shown in Fig. 5 is arranged on the light receiving surface PD1 And PD2 are arranged to vertically receive the imaging beam LBn from the imaging unit Un. In this embodiment, instead of detecting regularly reflected light from the reference patterns PTL1 and PTL2 on the outer circumferential surface of the rotary drum DR as described above with reference to Fig. 20, the photoelectric conversion elements DTo (Or the beam for drawing LBn) by directly detecting the origin point detection beam Bgb (or the imaging beam LBn) by using the reference point signal SZn '(or the origin signal SZn before correction) To measure the deviation.

In the first embodiment shown in FIG. 3, the origin detecting sensor (lens system GLb and photoelectric conversion element DTo) is provided with an origin detecting beam LBn projected from a light source different from the drawing (processing) And photoelectrically detects the reflected beam Bgb in the polygon mirror PM of the light source Bga. 3, after the reflecting surface RPa of the polygon mirror PM reaches the angular position of RPa ', the reflected beam Bgb reflected by the reflecting surface RPa is reflected by the f? Lens system FT, . the reflected beam Bgb incident on the f? lens system FT can be condensed on the upper surface side (the rotary drum DR side) of the f? lens system FT like the imaging beam LBn. Therefore, in the present embodiment, the reflected beam Bgb of the origin detecting beam Bga which is scanned by the polygon mirror PM and made incident on the f? Lens system FT is reflected on the rotary drum DR Is detected by the photoelectric conversion element DTo provided. In the present embodiment, in a state in which the substrate P is not supported by the rotary drum DR, or in a state in which the transparent region of the substrate P is supported by the outer peripheral surface of the rotary drum DR, The measurement is performed by the photoelectric conversion element DTo provided in the photodiode DR. In the present embodiment, the photoelectric conversion element DTo can receive both the origin detection beam Bgb and the imaging beam LBn while the rotary drum DR is stopped. In this case, the scanning speed of the imaging beam LBn traversing the photoelectric conversion element DTo of FIG. 23 becomes equal to the scanning speed of the origin detection beam Bgb. Therefore, the time at which the spot light of the origin detection beam Bgb is located and the origin time point Tog 'of the correction origin signal SZn' at the center position of the light receiving surface of the photoelectric conversion element DTo in FIG. (Or the origin time Tog of the origin signal SZn before correction) is displayed using the clock signal CCK obtained by sieving, for example, as shown in Fig. 19, (Reproducibility, deviation of the origin interval time Tab to Tha) of the reference signal SZn '(or the origin signal SZn before correction) can be checked.

Claims (23)

A beam scanning apparatus for projecting a working beam on each of a plurality of reflecting surfaces of a rotary polygonal mirror rotating around a rotating shaft and scanning the working beam reflected by each of the plurality of reflecting surfaces via a main optical system on a workpiece,
An origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror is at a predetermined prescribed angle;
And a correction unit that generates a correction origin signal corrected by a correction value according to a deviation of a time interval of the origin signal generated corresponding to each of the plurality of reflection planes. The method according to claim 1,
And a control unit for controlling the timing of projection of the processing beam onto the subject to be irradiated based on the correction origin signal. The method according to claim 1 or 2,
Further comprising a calculating section for correcting the deviation of the time interval of the origin signal by correcting an error caused by the variation of the rotation speed of the rotary polygon mirror. The method according to claim 1,
Wherein the origin detecting section comprises: a photoelectric detector for receiving the reflected beam of the detection beam projected onto the reflection surface of the rotary polygonal mirror to generate the origin signal; and a condenser for condensing the reflected beam of the detection beam as a spot on the photoelectric detector And a converging optical system that makes the scanning speed of the spot crossing the photoelectric detector by rotation of the rotary polygonal mirror to be higher than the scanning speed of the processing beam on the object to be irradiated. The method of claim 4,
Wherein the scanning optical system has a refracting power for condensing the working beam reflected by each of the plurality of reflecting surfaces of the rotary polygonal mirror as a spot on the irradiated object,
Wherein the light converging optical system includes an optical element that has a refractive power smaller than the refractive power of the injection optical system and condenses the reflected beam of the detection beam. The method of claim 5,
Wherein the focal distance of the optical element in the light converging optical system in accordance with the refractive power is made longer than the focal distance in accordance with the refractive power of the injection optical system. The method of claim 4,
Wherein the light converging optical system includes a reflecting optical member for reflecting the first reflected beam that is first reflected from the reflecting surface of the rotating polygonal mirror toward the reflecting surface of the rotating polygonal mirror, And an optical element which condenses the second reflected beam reflected by the first reflecting mirror onto the photoelectric detector as a spot. The method according to any one of claims 4 to 7,
Wherein the correcting section corrects the deviation amount by using the reference interval time obtained by dividing the rounding time corresponding to one rotation of the rotary polygonal mirror obtained from the interval of the generation time of the origin signal by the number of reflection surfaces of the rotary polygonal mirror And sets a correction value. The imaging beam is projected onto each of a plurality of reflective surfaces of a rotary polygonal mirror rotating around the rotation axis and the imaging beam reflected by each of the plurality of reflective surfaces is scanned on the object to be projected via the main optical system, A pattern writing apparatus for drawing a pattern on an object to be developed,
An origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror is at a predetermined prescribed angle;
A drawing control section for setting a time after a predetermined delay time from the generation of the origin signal as a start point of pattern drawing by the drawing beam,
And a correction unit that corrects the delay time set by the imaging control unit for each of the plurality of reflection planes by a correction value corresponding to a deviation of a time interval in which each of the plurality of reflection planes becomes the prescribed angle, . The method of claim 9,
Wherein the origin detecting section comprises: a photoelectric detector for receiving the reflected beam of the detection beam projected onto the reflection surface of the rotary polygonal mirror to generate the origin signal; and a condenser for condensing the reflected beam of the detection beam as a spot on the photoelectric detector And a converging optical system for making the scanning speed of the spot crossing the photoelectric detector by the rotation of the rotary polygonal mirror to be higher than the scanning speed of the imaging beam on the object to be irradiated. The method of claim 10,
Wherein the scanning optical system has a refracting power for condensing the imaging beam reflected by each of the plurality of reflection surfaces of the rotary polygonal mirror as a spot on the irradiated object,
Wherein the light converging optical system includes an optical element that has a refractive power smaller than the refractive power of the injection optical system and condenses the reflected beam of the detection beam. The method of claim 11,
Wherein the focal distance of the optical element in the light converging optical system in accordance with the refractive power is made longer than the focal distance in accordance with the refractive power of the injection optical system. The method of claim 10,
Wherein the light converging optical system includes a reflecting optical member for reflecting the first reflected beam that is first reflected from the reflecting surface of the rotating polygonal mirror toward the reflecting surface of the rotating polygonal mirror, And an optical element which condenses the second reflected beam reflected by the first reflection beam onto the photoelectric detector as a spot. The method according to any one of claims 10 to 13,
Wherein the correcting section corrects the deviation of the origin signal by using the reference interval time obtained by dividing the rounding time corresponding to one rotation of the rotary polygonal mirror obtained from the interval of the generation time of the origin signal by the number of reflection faces of the rotary polygonal mirror, And sets a correction value. The imaging beam is projected onto each of a plurality of reflective surfaces of a rotary polygonal mirror rotating around a rotation axis, and the imaging beam reflected by each of the plurality of reflective surfaces is scanned on a substrate supported on a supporting member via a main optical system A pattern writing device for writing a pattern on the substrate,
An origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror is at a predetermined prescribed angle;
A drawing control section for setting a time after a predetermined delay time from the generation of the origin signal as a start point of pattern drawing by the drawing beam,
A correcting unit correcting the delay time set by the drawing control unit for each of the plurality of reflection planes by a correction value according to a deviation of a time interval in which each of the plurality of reflection planes becomes the prescribed angle,
Wherein when the reference pattern formed on the support member or the substrate is scanned by the imaging beam, a time between the generation time of the reflected light generated from the reference pattern and the generation time point of the origin signal is measured, And a measurement unit for obtaining a correction value according to the correction value. 16. The method of claim 15,
Wherein the metrology section has a photoelectric detector that receives the reflected light generated from the reference pattern through the main optical system and the rotary polygonal mirror and outputs a photoelectric signal corresponding to a change in the reflectance of the reference pattern. 18. The method of claim 16,
Wherein the scanning optical system condenses the imaging beam as spot light on the substrate,
Wherein the imaging beam is supplied from a light source device that performs pulse oscillation at a period in which the spot light partially overlaps with respect to the scanning direction of the spot light by the rotary polygon mirror. 18. The method of claim 17,
Wherein the measuring section has a waveform storing section for sampling the waveform change of the photoelectric signal from the photoelectric detector at a frequency higher than a frequency of pulse oscillation of the light source device. The imaging beam is projected onto each of a plurality of reflective surfaces of a rotary polygonal mirror rotating around a rotation axis, and the imaging beam reflected by each of the plurality of reflective surfaces is scanned on a substrate supported on a supporting member via a main optical system A pattern writing device for writing a pattern on the substrate,
An origin detecting section for generating an origin signal each time each of the plurality of reflection surfaces of the rotary polygonal mirror is at a predetermined prescribed angle;
A drawing control section for setting a time after a predetermined delay time from the generation of the origin signal as a start point of pattern drawing by the drawing beam,
A correcting unit correcting the delay time set by the drawing control unit for each of the plurality of reflection planes by a correction value according to a deviation of a time interval in which each of the plurality of reflection planes becomes the prescribed angle,
A time between a generation time point of a photoelectric signal obtained when the photoelectric conversion element is scanned by the imaging beam and a generation time point of the origin signal is set to And obtaining a correction value corresponding to the deviation by measuring the pattern. The pattern writing apparatus according to claim 19,
Wherein the origin detecting section comprises: a photoelectric detector for receiving the reflected beam of the detection beam projected onto the reflection surface of the rotary polygonal mirror to generate the origin signal; and a condenser for condensing the reflected beam of the detection beam as a spot on the photoelectric detector And a converging optical system for making the scanning speed of the spot across the photoelectric detector by rotation of the rotary polygonal mirror to be higher than the scanning speed of the imaging beam on the substrate. The method of claim 20,
The detection beam is set to be incident on the scanning optical system before the imaging beam is incident on the scanning optical system as the rotary polygonal mirror rotates,
Wherein the photoelectric conversion element provided in the support member receives a spot of the detection beam condensed by the injection optical system. 23. The method of claim 21,
Wherein the scanning optical system condenses the imaging beam as spot light on the substrate,
Wherein the imaging beam is supplied from a light source device that performs pulse oscillation at a period in which the spot light partially overlaps with respect to the scanning direction of the spot light by the rotary polygon mirror. A projection optical system for projecting the imaging beam onto each of a plurality of reflective surfaces of a rotating polygonal mirror rotating around the rotation axis and projecting the imaging beam reflected by each of the plurality of reflective surfaces onto a spot 1. A method of inspecting the accuracy of a pattern writing apparatus for condensing light and scanning the pattern in a main scanning direction,
Wherein a plurality of reflection surfaces of each of the plurality of reflection surfaces of the rotary polygonal mirror are set to a specific origin signal generated when a specific reflection surface of the rotary polygonal mirror reaches the prescribed angle, Setting the inspection pattern to be drawn by the scanning in the main scanning direction of the spot light by the specific reflection surface in response to the scanning,
Scanning the inspection pattern while moving the substrate in a sub-scanning direction crossing the main scanning direction by a distance smaller than the size of the spot light during an interval time of the specific origin signal repeatedly generated by rotation of the rotary polygonal mirror , &Lt; / RTI &
Repeating the setting step and the drawing step with different specific reflection surfaces of the rotary polygonal mirror,
And measuring the shape of the inspection pattern drawn on the substrate or the deviation of the arrangement in the main scanning direction to check the precision of the origin signal.

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